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Featured Article:
The Unique Paths of Isaac
Newton and G.W. Leibniz to
the Calculus,
With Shared yet Underappreciated
Influence from Thomas Hobbes
by Liz Rogawski
about eurj
The Emory Undergraduate Research Journal (EURJ) is an annual print and online publication that accepts research manuscripts
written by Emory undergraduates from all academic disciplines.
EURJ provides a venue for students to showcase their high quality, original research while fostering interest in undergraduate research. Research can be submitted up until two years post-graduation. EURJ was founded through generous support by the Office
of Undergraduate Education and continues to enjoy support from
the Media Council, a division of the Student Government Association.
For more information, please visit www.eurj.com.
emory
undergraduate
research
journal
Volume VI,
Fall 2010
1655 North Decatur Road, Atlanta, Georgia 30322
staff letter
Editorial Board
Carolyn Gulas
Editor-in-Chief
Natural Sciences Editors
Alex Wein
Section Editor
Esther Yang
Uneeb Rahman
Moiez Ali
Michael Cranford
Chris White
Social Sciences Editors
Emma Accorsi
Section Editor
Shin-he Yu
Gabrielle Settlemire
Humanities Editors
Arjun Seth
Section Editor
Anni Pullagura
Zane Zeigler
Special Features Editor
Gabrielle Settlemire
Graphics and Layout Editors
Shahein Tajmir
Lead Designer
Kerri Woodward
Chief Technical Officer
Shahein Tajmir
Publicity
Diana Woodall
Yamini Potini
Bryan Bartlett
Copy-Editors
Philip May
Jessica Cheng
Financial Officers
Deborah Yang
Chief Financial Officer
Jessica Moore
Ethan Sobol
Dear Reader,
I am pleased to present to you the Fall 2010 issue of
the Emory Undergraduate Research Journal, an annual
publication that seeks to bridge the gap between undergraduate student researchers and the task of locating a
venue for publishing outstanding research. We at EURJ
acknowledge the exceptional work that Emory undergraduate students accomplish through their quality research, and our journal seeks to gain recognition for these
accomplishments by presenting your work to our fellow
peers and the broader Emory community.
This issue features four full manuscripts, two extended abstracts, and three special features articles for
your reading pleasure. Our feature article, “The Unique
Paths of Isaac Newton and G.W. Leibniz to the Calculus, With Shared yet Underappreciated Influence from
Thomas Hobbes,” offers readers an incisive look into the
philosophical foundations of the mathematical field of
calculus and the independent genius of two of history’s
greatest thinkers. Our special features articles delve into
such diverse topics as stem cell research, the psychology
of happiness, and factors that determine career choices
for students.
I hope that this issue of EURJ gives you a glimpse
into the seemingly endless array of research opportunities and topics that are open to the inquisitive Emory
undergraduate student. To continue our mission, we are
constantly looking for new submissions from students in
all subject areas. Every manuscript submitted to EURJ
undergoes a blind peer review, and in that regard, we are
always happy to welcome new faculty, post-doctorate fellows, and graduate students who can help out in this capacity.
Please be on the lookout for the submission deadline
for the next issue of EURJ, coming this fall.
Warmest regards,
Carolyn Gulas
contents
Critical Mass Representation in Uganda
p. 6
Converting Personal Interests into Research Studies: What
Factors Determine the Career Choices of Our Generation?
p. 7
The Effects of Visual Media on Students’ Efforts to Conserve
Energy in “Green” Residence Halls
p. 9
Creating a New Future: Obama Lifts the Ban on Stem
Cell Research
p. 12
The Effect of REM Sleep on the Critical Period in the Visual
Cortex
p. 13
The Unique Paths of Isaac Newton and G.W. Leibniz to the
Calculus, with Shared yet Underappreciated Influence from
Thomas Hobbes
p. 17
Can You Get a PhD in Happiness?
p. 21
A Neurological and Theoretical Review of Metaphor
Comprehension
p. 24
The Freshman Fifteen: A Case Study at Emory University
p. 31
Critical Mass Representation
in Uganda
Cynthia Adi
‘10 C
summary
Since the early 1990s, women’s rights activists have vociferously advocated the adoption
of quotas that ensure critical mass representation of women in legislatures worldwide. This
theory dates back to the 1970s and argues that the interests of women will not be addressed
until a critical mass of 30 percent is achieved. Critical mass theory is predicated upon the
assumption that female legislators will seek to guard the interests of women and improve
women’s quality of life due to their shared gender. The adoption of quotas to achieve critical
mass representation continues to grow in popularity amongst governments increasing from
just four countries in 1985 to eighty-four countries in 20061. Despite the widespread support for critical mass representation, relatively little is known about the actual contribution
of female legislators to the advancement of women’s human rights. Recognizing the importance of that missing knowledge, this research examines the influence of female members of
parliament (MPs) on women’s land rights in Uganda. Research was conducted for six weeks
in Kampala, Uganda with the support of the IDN-CIPA scholars program.
This research was non-experimental and qualitative. The study population was composed of the following: all former/current female members of parliament, male MPs of the
8th parliament (2006 – 2011), the directors of local NGOs, and reporters. Key informants
were identified through purposive sampling. Individuals selected to participate in the research were those with knowledge on women’s rights and/or land rights in Uganda. Research
methods include: observation of study populations, unstructured interviews, questionnaires
and access to primary resources, including government documents.
It was found that since 1995, women have been widely represented at all levels of the
Ugandan political system. Despite their widespread presence, the political authority of female politicians is routinely challenged by popular perceptions of women’s roles that are
steeped in patriarchy. In addition, the fact that women are unwilling to commit social and
political suicide by forgoing their traditional role as wife and mother has immediate implications on their ability to successfully lobby for radical changes in land tenure policies. The
female parliamentarians of the 6th parliament are credited with securing the land rights of
women through the passage of the 1998 consent clause, which requires spousal consent for
the sell of any family land. Attempts have also been made by the female parliamentarians of
the 7th and 8th parliament to improve women’s land rights. However, the policies championed in these parliaments have languished due to executive interference, patriarchal reluctance and the failure of female politicians to coordinate with women’s organizations.
The adoption of quotas, that ensure critical mass representation, does not automatically
lead to improved rights for women. One rationale for this is that female politicians must
contend with a patriarchal system that limits their actions. Secondly, not all women who
enter politics are motivated by a desire to improve women’s rights. Evidence from Uganda,
however, suggests that the latter can be overcome if women’s NGOs train and equip female
politicians with knowledge of gender consciousness and gender budgeting.
1
Tripp, A. M., & Kang, A. (2008). The global impact of quotas - On the fast track to increased female legislative representation. Comparative Political Studies, 41(3), 338-361. doi: 10.1177/0010414006297342
Cynthia Adi graduated in
the spring of 2010 with a
BA in International Studies and a minor in African
Studies. At Emory, Cynthia routinely volunteered
with the International Resuce Committee as a family
mentor to refugee families.
She is currently working in
Uganda with the Foundation for Sustainable Development.
Converting Personal Interests into Research Studies:
What Factors Determine the Career Choices of Our Generation?
An Interview with Tracy Scott, PhD
By Gabrielle Settlemire
Dr. Tracy Scott has been a lecturer in the Emory University Department of Sociology since 2004, and has a strong enthusiasm for research in addition to teaching. In this interview, Dr. Scott explains her most recent research study, which is particularly interesting because of its relevance to the
lives of current Emory undergraduate students. Dr. Scott is currently looking at the career decisions of undergraduates and what factors influence
such decisions. As a student of Dr. Scott’s, I see her genuine interest in what she does and this enthusiasm shines through in the words she spoke to me.
I hope that this article will be an inspiration to Emory students to get involved in research, research that they genuinely enjoy.
Gabby: What has been your favorite research study you have completed
so far in your career?
Dr. Scott: That’s a good question...that I’ve completed. Can I have
two?
Critical Mass Represention - A theory that contends that women’s interests
will only be addressed by
governments when women
represent a critical mass of
at least 30 percent.
Yeah.
I actually really enjoyed my dissertation, which was about how religion influences people’s attitudes about their work. And, I also
looked at gender as well. So I looked at religion and gender together
and how that influences people’s attitudes about work. I had a survey that my advisor had conducted that I analyzed and then I did
fifty in-depth interviews to supplement that survey. So I was able to
look at some broad results in a national U.S. population from the
survey and then try to understand those survey results by talking
to people in-depth about their views on faith and work. So, it was
really fascinating and I love to talk to people so the interviews are
fun to do. The second project that was a favorite was in an entirely
different area, which is healthcare research. I did a study, another
qualitative study, doing in-depth interviews with nurses and physicians about their interactions in the hospital. So I looked at two
different hospitals in the Atlanta area and interviewed nurses and
physicians who worked together on the same unit in the hospital.
That was fascinating to get to talk to people and really understand
things in-depth that they deal with in their work on a daily basis
and having to interact with their coworkers.
That sounds really interesting. What has influenced you to perform your
own research studies and what satisfaction have you gotten out of it?
That’s another very good question. I think a lot of research stems
from personal interest that we then turn into something more objective and systematic. My dissertation research came from a personal interest I had, because it took me a very long time to figure
out what I wanted to do with my life and my career. So part of my
motivation for the dissertation was to understand how other people
thought about their work and how they came to decide on careers
and whether their religious background mattered at all, whether being a man or woman mattered at all. So I took my personal interest
and then looked at some things in the sociological literature that
past theorists said are important, which was religion and gender. So
I tried to take my personal interest and look at it a bit more objectively and look at what people have done in sociology in the past
and tried to build on that with actual research.
What career paths were you considering before you decided on being a
sociology professor and researcher?
My first career
interest
was
business, then I
thought
about
working in the
publishing
industry. Then I
thought
about
law school. I actually
applied
and got in but
didn’t go. Then I
realized I wanted
to teach at the
college
level,
but I originally
thought I would
do a PhD in religion. While getfall 2010 – eurj
7
ting a masters in religion, I was influenced by my mentor who suggested I do sociology of religion so that I could be a bit more broad
and study more things. Then I ended up there.
Can you summarize the goals of your current research?
Certainly, I did a stint in healthcare research for about seven or
eight years and now I’ve come back to more purely sociological research - wanting to get back into the field of career interests and
work values. I’m now looking at undergraduates and how they
think about their future careers, how they’re trying to make decisions. I have left the religion influence, but I still want to focus on
gender, now adding in race and ethnicity, to see how different social
backgrounds of people influence how they think about work, how
they think about this large aspect of their life, and how they try to
make decisions about it. So, I’ve done a pilot project with a SIRE
student last summer. I conducted four pilot interviews and she conducted another nine for me. So we did thirteen interviews of undergrads with men, women, African Americans, and whites trying
to see if there are some differences in how people from different
racial-ethnic backgrounds and men and women are thinking about
these things.
And have you found that there are so far?
We think there are, yes. Again, because it’s early stages it is kind of
suggestive but it does seem like there might be some differences,
yeah.
Where did you find the idea for that research?
Part of it came from my dissertation because it’s kind of connected.
And part of it actually came—a big motivation simply came from
talking to the undergraduates that I teach. Many of them come in
with questions about what they should do and so just in conversation it was so interesting to me to hear how different people were
thinking about this. But again, I thought I’d like to do this more
systematically and try to understand what’s going on with this generation in terms of major influences in the career path.
Can you offer any advice for undergraduate students wishing to conduct
research?
Yes, for undergrads wishing to conduct research, always pick a topic
that you’ve got some kind of interest in because you are going to
spend a lot of time with this topic. You want something you aren’t
going to get bored with. Again, try to look and see how something
you’re personally interested in could be approached from a more
academic, objective perspective in whatever discipline you are looking at. And I think oftentimes that makes for the most interesting
research.
Gabrielle Settlemire is a junior and plans to
major in Mathematics and Economics. She is
a resident of Edmond, Oklahoma and hopes
to go to medical school after graduating from
Emory.
8 eurj – fall 2010
Do that
funky
research,
emory
boy!
The Effects of Visual Media
on Students’ Efforts to Conserve Energy in
“Green” Residence Halls
Dolly Krishnaswamy
‘12 C
faculty advisor:
Matthew Campbell is a Living Links postdoctoral fellow and an ORDER teacherscholar for 08-09. He is working with Professor Frans de Waal and studying empathy in
chimpanzees at the Yerkes National Primate Research Center. He received his Ph.D. in
psychology at the University of Wisconsin-Madison in 2006, and graduated from Emory
College in 1999 majoring in Neuroscience and Behavioral Biology.
Submit to ...
eurj
Rebecca Lipman
Frances Nicholas
Rebecca Lipman is a junior
from Providence, Rhode
Island majoring in Theater
Studies. She has enjoyed
her first year at Emory participating in Ad Hoc Theater’s production of “You’re
A Good Man, Charlie
Brown,” playing tennis for
Emory’s club team, and volunteering on campus.
Frances Nicholas is an economics major with a minor
in global health, culture and
society. Over the past year
she has been involved in volunteering around campus,
as well as being a member of
Kappa Kappa Gamma and
on the equestrian team. She
plans to go to public health
school in the future.
‘12 C
‘12 C
Dolly Krishnaswamy is a Biology and Journalism major
at the College. She volunteers at a research lab at Emory and works as an intern
at a law firm in Atlanta. She
hopes to go to law school in
the future.
Sarah Rattan
‘12 C
From Houston, Texas,
Sarah is an economics major, Spanish minor. For
the past year at Emory she
has worked with Hand in
Hand, PAWS, served as
Miss Black & Gold for Alpha Phi Alpha, and is the
cheer captain of Emory’s
newborn cheerleading team.
Introduction
As the fairly new millennium progresses, issues concerning the
need for alternative energy to sustain our environment have become
more and more pressing. Today, the efforts to conserve energy are
limitless: from the popularization of the term “living green” in new
fashion trends to the potential use of algae for fuel in cars. It is becoming evident that everyone has a part in using or discovering alternative energy, conserving energy, and living green in general. At
Emory University, the resources available to promote green living
are plentiful. There is no reason for its students to be “environmentally unfriendly”. This new term of “environmentally unfriendly”
encompasses any action (or inaction) that consumes high amounts
of energy. Most recently, Emory University has added three new
green buildings: Few, Evans, and New Turman, each equipped with
many energy conserving features and a “green screen” to monitor
energy use. the advertisement of “green life”, however, varies within
these buildings. Few and Evans contain plenty of signs and posters
promoting sustainability. New Turman, however, lacks this form
of green encouragement all together. In this study, we will observe
the effects of visual media on students’ efforts to conserve energy
by equipping New Turman residence hall with an identical set of
“green promotion” posters. In an effort to assist Emory in their alternative energy/ sustainability efforts, we will discover how helpful
visual media are in decreasing the amounts of energy used. Will
there be any change at all or does the amount of energy used stay
constant or even increase?
Topic Question & Hypothesis
How do visual media influence people’s responses to the green
movement? This is the study’s motivating question. Before beginning the experiment, we hypothesized that if visual media that
encourages the green movement is introduced into New Turman,
then people will be more sustainable, resulting in conservation of
resources, specifically electricity and water usage, which will be reflected by the “green screen”.
Methods
We recreated sustainability-encouraging posters that were on
display in Few and put them up in New Turman. Recreating the
same posters provided a constant variable and eliminated the advantage of more-attention-grabbing sizes, colors, green phrases, etc.
Then from the green screen in New Turman and Few we collected
data on electricity usage (kWh/ day), steam consumption (kiloBTU/day), chilled water consumption (kilo-BTU/ day), and all systems (kilo- BTU/day) for a period of two weeks each: before posters, with posters, and after posters. Because the visual media were
already present in Few and none were added or taken away, Few’s
data were used as the control to compare data from New Turman.
We compared these results to determine an overall trend of the effects of green media and the length to which these effects lasted.
Discussion of Results
With a first look at our data, it appears that the numbers recorded by the green screen support our hypothesis and visual media encouraging the green movement do encourage students to be
more sustainable. The all systems usage measurement provided by
the green screen gives a generic reading of all the basic functions
of the New Turman building. This measurement showed a mean
difference of 3057.36 kilo-BTUs between New Turman before the
10 eurj – fall 2010
posters were displayed and the period while the posters were up. A
difference this large could only have occurred 0.01% of the time
by chance alone, and so it is safe to say that something other than
chance was influencing the Turman residents’ energy usage.
When we took a more in depth look at the specific energy
measurements from the green screen, we were able to pinpoint exactly what type of energy the New Turman residents were conserving. The drop in electricity usage was not statistically significant, so
we know that this was not the cause of a decrease in energy usage
for the period while the posters were displayed. Steamed water usage, which is used to heat water for showers, rose in a statistically
significant way. This makes sense because the control period was in
the beginning of October whereas the experimental period was at
the end of November, and so temperatures would have dropped,
therefore causing students to use more hot water for showers, washing their faces/hands. Additionally, the hot water is used to heat
the building, and so it makes sense that as students turned up their
thermostats, steamed water usage rose. The main decrease was in
chilled water consumption. This makes sense given the difference in
temperature between the two time periods being compared. Chilled
water consumption measures water used for showers, sinks, washing
machines, flushing toilets. Although the colder temperatures could
cause students to use less cold water, it is also possible that the posters were encouraging students to use the energy efficient toilets correctly (flushing up only recycles the water in the bowl rather than
completely flushing), use less water when brushing their teeth or
washing their hands, and participate in other water saving activities.
Our next comparison was of energy usage in New Turman
while the posters were on display and the period of time after they
came down. We hypothesized that while the posters were up, energy
usage would decrease and would rise again after we took the posters
down. Without the posters to consciously remind them, students
would forget to conserve their energy usage.When comparing the
all systems usage while the posters were up versus after they came
down, we found a statistically significant drop in overall energy use.
The results were contrary to our hypothesis, but after speaking to
Dolly, a New Turman resident, she told us that the posters had been
noticed and brought up in a ResLife meeting, and ResLife had independently decided to continue encouraging the green movement
in New Turman, which would explain the continued decrease in resource use even after our posters were taken down.
We also compared the data from New Turman to the data from
Few. We hypothesized that the energy usage in New Turman would
be greater than Few for the period before the posters went up, because Few has posters encouraging the green movement. We found
that the data supported our hypothesis and showed a statistically
significant difference in all systems energy usage for the period before the posters were put up in New Turman. With a closer look at
the specific energy usage, we found that the difference in electricity
usage between the two dorms was not statistically significant. The
environmentally friendly posters in Few did not seem to be affecting the residents’ electricity usage. However, there was a statistically
significant difference in chilled water consumption and steamed
water consumption between the two dorms. New Turman used
less steamed water than Few, but New Turman residents used far
more chilled water than Few residents. This seems to show that the
sustainable posters in Few are mostly encouraging activities which
would decrease use of water for toilets, sinks, washing machines,
Few residents consciously choosing to use the energy-efficient toilets correctly, turn off water while brushing their teeth, and avoid
leaving running water in their sinks whenever possible could account for this difference.
During the period while the posters were on display in New
Turman, we expected the data from New Turman’s green screen to
match the data from Few’s green screen. Since the time period was
the same for both sets of data, we knew that factors like temperature and time of the season would not skew the data. When looking
at the all systems usage between the two dorms, we found a statistically significant difference in energy usage. Few was using an average of 5802.36 kilo-BTUs, while New Turman was using a mean of
only 2213.14 kilo-BTUs. This is a very large difference. Obviously
something had occurred in New Turman during this time period
to drop their energy usage. The data seem to support our hypothesis that energy usage would drop while the posters were on display.
It is possible that since the Few residents had been exposed to the
posters since the beginning of the school year, they had become accustomed to the posters and stopped noticing them as much. In
contrast, the posters were newly put up in New Turman, and perhaps, the residents took morenotice of the posters and drastically
dropped their energy consumption.
Next we looked at which specific energy features the New Turman residents had conserved versus Few residents. We found that
although the difference in chilled water consumption was not statistically significant, both the difference in electricity usage and the
difference in steamed water consumption was statistically significant. This shows that New Turman residents were careful in turning
off lights, unplugging their electronics when done charging, and using the elevator less frequently which were all things that our posters advocated.
Lastly we compared data from New Turman from the week after the posters came down to the same week in Few. We found that
overall energy usage was significantly less in New Turman than in
Few, and that the difference in steamed water consumption and the
difference in chilled water consumption was statistically significant.
New Turman was using more chilled water than Few in this period,
which supports our hypothesis that the energy usage in New Turman would rise again after the posters were taken down. However,
the fact that the all systems usage is still significantly lower in New
Turman after the posters were taken down, both between Few during the same time period, and also when compared to New Turman
while the posters were up, does not support our hypothesis. In the
period after the posters were taken down, New Turman was using a
significantly lower amount of steamed water than Few. This seems
to show that the measures to continue energy conservation by ResLife in New Turman were successful.
Overall, the statistically significant drop in energy usage between New Turman before the posters and while they were displayed seems to provide support for our hypothesis. The significant
difference in energy usage between Few and the period of time New
Turman had posters displayed provides support. However, more research would need to be done to further confirm our results. Longer time periods would need to be compared, and the project would
need to be duplicated in another dorm to provide added support
that the posters were the variable affecting energy usage. Also, further research would have to be done to ascertain exactly which posters were making the most difference in terms of energy consumption (the ones reminding students to take the stairs, or turn off the
lights, or take shorter showers, etc.) Our hypothesis also needs to
be altered based on the results we have. Based on the data, it seems
that the posters affect energy usage and result in a decrease in energy. Furthermore, the energy conserving habits last even after the
posters are taken down. These results can be applied to many other
living situations, such as apartment buildings. From our experiment
there is evidence that green movement posters do have an effect on
energy conservation habits and the possibilities of where you can
use this type of media is endless.
Conclusion
In conclusion, we found the experimental methods and procedures to be highly fair to have conducted the proposed experiment.
Therefore, we can be sure that the resulting data/outcome is accurate and supports the hypothesis Emory University students were
well educated enough to actively respond to the posters’ green encouragement. The information gained from this study is significant
and can be used to create greener environments on college campuses and places around the world.
Love the heat?
We need you
j
r
eu
!
y
l
t
en
fall 2010 – eurj
11
The Effect of REM Sleep on the
Critical Period in the Visual Cortex
Tania del Rivero
‘10 C
abstract
Creating a New Future
Obama Lifts the Ban on Stem Cell Research
An Editorial by Lauren Kurlander
O
n March 9, 2009, President Obama issued an executive order to reverse President Bush’s strict limitations
on stem cell research. President Obama has thrust
government support behind the research in hopes of
finding new treatments for serious diseases such as Parkinson’s and
Alzheimer’s. By reissuing the funding of this research, President
Obama stands by his pledge that “his administration will ‘make scientific decisions based on facts, not ideology’” (Stolberg NY Times,
3/9/09).
Although President Obama has opened the financial floodgates
of the National Institutes of Health, the Dickey-Wicker amendment of 1996 still bans scientists from manufacturing new stem cell
lines. Thus, all stem cell lines will continue to be the embryos remaining in private fertility clinics – still a heated debate of morality.
To quell the opponents of stem cell research, President Obama’s order will also “give the National Institutes of Health 120 days to develop ethical guidelines for the research” so that some caution tape
is set up for the anticipated boom in stem cell research (ABC News,
3/9/09).
Because the NIH grant application process can take as long as
nine months, the NIH is trying to “streamline the research process”
(ABC News, 3/9/09) by making grant money readily available. By
speeding up the grant processes, the NIH also hopes “to get money
from the stimulus out quickly” (ABC News, 3/9/09).
Revived by the new federal support, stem cell research is expected to open doors to many new possibilities. Here at Emory,
stem cell research is a popular and progressing field. According to
Elizabeth Rogawski, a revent Emory College graduate who worked
at Emory’s Stem Cell Research lab, the latest research conducted
here intends to create IPS cells, or induced pluripotent stem cells.
These cells avoid the use of embryos while still maintaining embryonic stem cell characteristics. The ability to manufacture stem cells
from adult cells would give a steady supply of stem cell lines to give
stem cell research another giant boost. Rogawski’s personal project
12 eurj – fall 2010
“is involved with reprogramming human dermal fibroblasts to stem
cells. My particular goal is to use over-expression of microRNAs
to induce these cells to have the same characteristics as embryonic
stem cells. This would provide an alternate source for stem cells
and circumvent some of the moral issues with funding, etc.” Ultimately, stem cell research is a critical area for the treatment of diseases, and other researchers at Emory actually deal with this specifically, working to treat various diseases with stem cells, such as heart
disease. This is undoubtedly a thriving field of study, and thanks to
Obama, stem cell research will only increase in the future.
Lauren Kurlander has transferred to Cornell
University where she plans to major in biopsychology. She is a resident of Manalapan, New
Jersey, and she hopes to pursue a career in neurology.
The critical period for synaptic plasticity is a limited time period for learning during which the brain must be exposed to certain stimuli. During this time, the brain is
more flexible and susceptible to change, but once the critical period closes, the stimuli no
longer have the same effect because permanent modifications have been made. Although
there is a difference in brain structure during and after the critical period, we have yet to
identify the environmental factors that contribute to its closing. Recent studies suggest
REM sleep plays a key role in this process by reducing the time period to induce synaptic
plasticity in the visual cortex. To test this hypothesis, a group of Sprague Dawley rats was
deprived of REM sleep for one week at the end of the critical period, about 5 weeks postnatal, using the “small-pedestals-over-water” method. A control group of Sprague Dawley rats lived under similar conditions, but with necessary adjustments allowing them
to sleep. Slices of visual cortex were obtained, and Long Term Potentiation (LTP) was
induced to layers II/III in sleep- deprived and control rat brain slices. While LTP was
observed in rats that underwent REM sleep deprivation, in the control rats, there was
no significant change after high frequency stimulation. These findings suggest that REM
sleep accelerates the closing of the critical period by reducing synaptic plasticity in the
visual cortex in rats.
Tania del Rivero is a recent
graduate of Emory College
with a BS degree in Neuroscience and Behavioral
Biology with a minor in
French. This research project was conducted while
she was studying abroad in
Santiago, Chile. Next year
she plans to attend graduate
school to pursue a PhD in
Neuroscience. In the future
she hopes to continue doing research exploring the
mechanisms behind learning and memory.
faculty mentor:
Dr. Bernardo Morales is a professor in the department of Chemistry and Biology
at the University of Santiago, Chile. He earned his doctorate at the University of Chile,
where he wrote his dissertation on “Inhibitory Responses Evoked by Odorants in Olfactory Neurons in Vertebrates”. Previously, he has worked as an investigator at the Department of Neuroscience in the Zanvyl Krieger Mind/Brain Institute of Johns Hopkins University. He is currently Principle Investigator of a Neuroscience laboratory which focuses
on the cellular mechanisms of learning and memory.
acknowledgements
My experiment is based on the work of James Shaffery and uses simliar methods to
explore the same set of topics. I would like to thank my mentor, Bernardo Morales, for
his guidance in experimental design, as well as Carlos Rozas for his assistance in the procedure. I would also like to thank Kristen Frenzel for her suggestions. I would like to acknowledge the University of Santiago Chile and the Institute for Study Abroad at Butler
University along with Emory University for providing me with resources and guidance.
Synaptic Plasticity - the
ability to alter the efficiency
and structure of a synapse as
a result of electrical stimulation
Long Term Potentiation
(LTP) - a model of synaptic plasticity resulting in the
strengthening of a synaptic
connection between two
neurons after high frequency stimulation
Introduction
During early childhood and through a short critical period, the
cerebral cortical circuits display a high plasticity state that can be
easily modified. The sensory experience is essential for the normal
maturation of circuits in many regions of the cortex during these
critical periods. For example, children with cataracts lose vision in
the affected eye unless they have a surgery before puberty. Another
example of processes related to the critical period is the learning of
a second language before puberty in order to gain complete fluency.
Finally, a remarkable example of plasticity is the activation of the
primary visual cortex during Braille reading in blind people who
have lost their vision at an early age.
Most of our understanding of plasticity during the critical period derives from studies of ocular dominance (OD) in the visual
cortex. OD is the relative response of a neuron to visual stimulation of the right versus the left eye. Wiesel and Hubel did the first
demonstration that monocular deprivation causes ocular dominance shift. [1] Numerous studies of deprivation have shown that
OD shifts involve rearrangement of inputs from Lateral Geniculate
Nucleus (LGN) to layer IV and also from layer IV to layer III. Considerable progress has been made toward understanding the molecular and cellular basis of experience-dependent plasticity in cortex.
It is now well established that cortical re-organizations are driven by
changes in the patterns of activity induced by alterations in sensory
experience. [2] The cellular mechanisms of this type of plasticity
and the factors that confine it to a short critical period are poorly
understood. Factors, such as the N-methyl-D-aspartate (NMDA)
glutamate receptor, metabotropic glutamate receptors (mGluRs),
neurotrophins, brain-derived neurotrophic factor (BDNF) and
nerve growth factor (NGF), and GABAergic currents, have been
implicated in the determination of the critical period. Rapid Eye
Movement (REM) sleep has recently been implicated in this process
as well.
Receiving the appropriate stimuli during the critical period
is essential for normal development. Since this period of time is
characterized by increased synaptic plasticity, only then are certain
stimuli and experiences able to shape the brain by making the necessary synaptic modifications. Once the window for the critical period closes, the changes made during this time become permanent.
For example, in an experiment conducted on kittens, one group
was deprived of visual input in one eye throughout the critical period and became permanently blind in the light-deprived eye even
though the eyes received normal visual input following the critical
period. Another group of kittens that was deprived of visual input
in one eye for part of the critical period was able to regain vision
in that eye as long as they received visual input within the critical
period. [3] Although the amount of visual input was the same in
both groups, the time at which the input was exposed to the kittens
drastically changed the impact on synaptic connections.
This brings up the following question: What determines the
length of the critical period? Previous studies have demonstrated
the involvement of BDNF and GABAergic currents in controlling the time course of the critical period in visual cortex. [3, 4]
Although environmental factors controlling the critical period are
not well understood, one element considered to have an effect is
REM sleep. REM sleep is a sleep stage that occurs every 90 minutes
after the initiation of sleep and is characterized by Rapid Eye Movements (REM). This sleep stage has also been tied to memory consolidation which involves permanent synapse modifications. [6] In
experiments done on kittens, monocular vision deprivation reduced
14 eurj – fall 2010
the response to stimuli in that eye. After sleeping 6 hours, this effect was enhanced and the kittens respond less to stimuli than the
kittens which did not sleep during that time. The lack of response
to stimuli indicates that the synaptic plasticity was reduced. [7]
Experiments conducted by James Shaffery on the visual cortex of
rats suggest that REM sleep deprivation is capable of maintaining
synaptic plasticity beyond the 5 weeks. [8] This implies that REM
sleep reduces synaptic plasticity and has the potential to promote
the closing of the critical period.
A reliable model for testing synaptic plasticity in the brain is
Long Term Potentiation (LTP). LTP is a form of synaptic plasticity that commonly occurs in the central nervous system (CNS).
This model has been proposed to reflect the means by which the
brain stores information in learning and the memory through cellular and molecular mechanisms and is one of the most widely
accepted models by which synaptic plasticity is carried out in the
visual cortex. LTP is measured by a prolonged increase in postsynaptic response after a brief episode of strong synaptic activation,
typically presynaptic tetanic stimulation at 100 Hertz. First, low
frequency stimulation is applied until a baseline is obtained, then
trains of high frequency stimulation known as tetanus are applied.
The change in the postsynaptic response is measured as an increase
in the amplitude of field excitatory postsynaptic potential (fEPSP).
A greater postynaptic response represents a stronger synapse because
of greater signal transmission. This increase in amplitude of the
fEPSP may last hours, days, or even weeks, depending on the type
of stimulation protocol. Since inducing LTP signifies that a synapse
is capable of changing in strength and efficacy, it is a good indicator
of synaptic plasticity.
In the following experiment, the LTP model was used to compare synaptic plasticity in the visual cortex at the end of the critical
period in REM sleep-deprived rats and in control rats with normal sleeping patterns. The objective of this research is to establish
if REM sleep plays a role in the duration of the critical period. In
accordance with earlier evidence, we hypothesized that REM sleep
brings about the end of the critical period by decreasing the overall synaptic plasticity in the brain. Using sleep deprivation during
critical period formation in rats, we compared the ability to induce
LTP in the visual cortex in sleep-deprived versus normal rats at the
end of the critical period. Normally, in 5 weeks old rats at the end
of the critical period, it is impossible to induce LTP from stimulating white matter (WM) since they have lost most of their synaptic
plasticity. Here we show that at 5 weeks old, while the control rats
showed no change in the postsynaptic response after tetanic stimulation, the REM sleep-deprived rats managed to produce LTP. This
demonstrated that REM sleep reduced the time course to induce
synaptic plasticity in the visual cortex, and in doing so, brought on
the closing of the critical period.
Materials and Methods
REM Sleep Deprivation
Twenty-eight (28) day old Sprague Dawley Rats were placed
inside plastic REM deprivation pools. These pools had a cylindrical platform located at the center of the base which measured 7 cm
in height, 10 cm in diameter and was surrounded by water with a
depth of 3 cm. These precise measurements allowed rats to stand on
the platform without difficulty, but if their muscles began to relax,
they fall off the platform into water. Using this method, the rats
were prevented from reaching the REM stage of sleep for 7 days.
When cleaning the pools these rats were allowed approximately 60
minutes of sleep, which was not sufficient amount of time to reach
the REM stage. The group of 28 day old control rats lived in pools
with the same measurements and depth of water, with the exception of a central platform measuring 26 cm in diameter that provided the rats with sufficient floor space for sleep.
Brain Dissection
At 35 days, the rats were anesthetized and decapitated using
a guillotine. The brain was obtained and the necessary cuts were
made to isolate the visual cortex. Then, using a vibratome (Campden Instrument), 300 to 400 µm thick brain slices were obtained
in a dissection buffer at 4ºC containing: 212.7 mM sucrose; 5 mM
KCl, 1.25 mM NaH2PO4; 3 mM MgSO4; 1 mM CaCl2; 26 mM
NaHCO3, and 10 mM glucose (pH 7.4 bubbling with 95% O2
and 5% CO2). Eight slices were obtained for each group of rats.
The slices were transferred onto nylon squares and then placed into
a storage chamber containing artificial cerebrospinal fluid (ACSF)
made of: 124 mM NaCl; 5 mM KCl, 1.25 mM NaH2PO4; 1 mM
MgCl2; 26 mM NaHCO3, and 10 mM Glucose (pH 7.4 bubbling
with 95% O2 and 5% CO2). The slices remained in the storage
chamber for an hour at 32ºC before electrophysiological recordings
were executed. This investigation was performed following protocols approved by the Animal Care and Use Committee of the University of Santiago in Chile.
Electrophysiological Recordings
Extracellular recordings for field excitatory postsynaptic potentials (fEPSPs) were made in the visual cortex slices by placing
a stimulus electrode in the white matter of the brain sample and a
recording pipette in the pyramidal cells of layers II/III within the
same cortical column. Synaptic responses were evoked with 0.2
msec pulses of 15-300 µA amplitude delivered using a bipolar stimulating electrode (FHC, 200 µm diameter). The white matter was
stimulated with a low frequency stimulus of 1 Hz every 15 min until a 20 min baseline was collected. Then tetanic stimulation, composed of 10 trains of 100 Hz separated by 5 seconds, was applied to
the white matter to induce LTP.
Figure 1 - Dual extracellular field recording showing the stimulation
pipettes on the white matter and recording pipettes on layer II/III.
Visual Cortex (WM -> II/III)
a) 3 Week-Old Rat
Results
Preliminary experiments were conducted in the laboratory to
compare synaptic plasticity in rats during and after the critical period using LTP. These experiments aimed to find a detectable difference in the synaptic responses between mature and immature
rats. Figure 2 shows the recordings of the fEPSPs in mV obtained
in layers II/III of the rat visual cortex, induced by tetanic stimulus
applied to the white matter at 0 seconds.
In the 3 weeks-old rat (Fig.2-a), the single recordings of the
fEPSPs clearly depict a greater amplitude in the fEPSP after the tetanic stimulus than in the fEPSP before stimulation. The amplitude
of the response nearly doubled from about 1.0 mV to 2.0 mV. In
the graph at the bottom, we can see this change in the amplitude after the tetanic stimulus is applied at 0 seconds. This increase in the
fEPSP lasts for more than 30 min, indicating LTP was produced
because the postynaptic response is increasing, thus strengthening
the synapse. This data suggests that at 3 weeks, rat brains retain synaptic plasticity. In the 5 week-old rats (Fig.2-b) however, the amplitude of the fEPSP before tetanic stimulation is almost the same size
as the amplitude of the fEPSP after tetanic stimulation. This evidence shows that the capacity to induce LTP from the white matter
declines with age and can be easily induced in young animals. With
this information and considering previous studies, we can deduce
that at 5 weeks there is no synaptic plasticity due to a closing of the
b) 5 Week-Old Rat
Figure 2 - The top figures are single recordings of fEPSPs (in mV) in
layers II/III of the visual cortex upon stimulating the white matter before (left) and after (right) tetanic stimulation in 3 week-old (a) and 5
week-old (b) rats. The graphs at the bottom show the amplitude of the
EPSPs in mV versus time in minutes. At 0 seconds, tetanic stimulus was
applied.
fall 2010 – eurj
15
critical period.
The data in Figure 3 demonstrate that 5 week-old rats subjected to REM sleep deprivation were capable of generating LTP
in response to tetanic stimulation applied to the white matter. The
increase in the percentage of baseline response (another measure
of fEPSP amplitude) after tetanic stimulation at 0 seconds was increased on average 30% and lasted about 30 min. In contrast, rats
with regular sleep cycles, as seen in the control rats, were incapable
of producing LTP as expected based on the data from Figure 2. The
fEPSPs before and after the tetanic stimulation are almost identical
in the control rats and the responses maintain the same amplitude.
In comparing Figures 2 and 3, we can see there was not as
much increase in the magnitude of the response in the LTP of the 5
week-old REM sleep-deprived rats in Figure 3 as in the 3 week-old
rats in Figure 2. In the 3 week-old rats, the amplitude of the fEPSPs
increased by 100%, from 1.0 mV to 2.0 mV, while in the 5 weekold REM sleep-deprived rats, the amplitude increase by approximately 30%, from 100% to 130%. However, the data clearly suggest that LTP was induced in the 5-week old REM sleep-deprived
rats because there was an unambiguous difference in the amplitude
of the responses in this group of rats and the control rats. The amplitudes of the fEPSPs were always larger in the REM sleep-deprived rats than the control rats after tetanic stimulus. In the REM
sleep-deprived rats, the fEPSP amplitudes increased from a 100%
baseline response to a 130% baseline response, while in the control
rats, the baseline response remained about 100% the entire time.
These data show that the REM sleep deprived rats retained synaptic
plasticity in the visual cortex, suggesting that REM sleep influenced
the amount of plasticity in the visual cortex. The most plausible explanation for the obtained results is that in the REM sleep-deprived
rats, there was a prolongation of the critical period, which normally
ends at 5 weeks.
Conclusion
It’s beneficial for us to learn more about the modulators of the
critical period because this information can be utilized to manipulate its duration. In the critical period, many structural and functional changes occur in the brain which cause its maturation and
limit its capacities by creating a fixed structure. Not only is it in our
interest to identify these changes, but also to find out the mechanisms which provoke them.
Previous studies by Shaffery & Roffwarg showed REM sleep
deprivation had no effect on LTP regulation in mature rats since the
critical period had already come to an end. [6] The current study
used immature rats to demonstrate that REM sleep is a key factor
involved in the mechanisms that contribute to the closing of the
critical period by reducing synaptic plasticity. This signifies that
REM sleep deprivation can extend the critical period. Information
such as this can be used to find out how we could have a more flexible brain for a longer period of time. If we can manipulate our critical period for learning, for example, we could learn a new language
or math concepts with the same ability of a 12 year-old at age 30.
Works Cited
[1] T.N. Wiesel, D.H. Hubel. Single-Cell Responses in Striate
Cortex of Kittens Deprived of Vision in One Eye. J Neurophysiol.
1963 Nov 26:1003-17.
[2] Frenkel MY, Bear MF. How monocular deprivation shifts ocular
dominance in visual cortex of young mice. Neuron 2004 Dec 16;
44(6):917-23.
[3] Olson, Freeman. Monocular deprivation and recovery during
sensitive period in kittens. J Neurophysiology 1978 41 (1), p. 65
[4] Morales, B., Young-Choi S, and Kirkwood, A. Dark rearing alters the development of GABAergic transmission in visual cortex. J.
Neurosci. 2002 22(18):8084-8090.
[5] Jiang, B., Huang, J., Morales, B. and Kirwood, A. Maturation
of inhibitory transmission and timing of plasticity in visual cortex.
Brain Research Reviews .2005 Dec ;50(1):126-33.
[6] R. Stickgold Sleep-dependent memory consolidation. Nature
Vol. 437 27 Oct 2005
[7] M.G. Frank, N.P. Issa, M.P. Stryker. Sleep enhances plasticity in
the developing visual cortex. Neuron 30, 275-287 (2001)
[8] James P. Shaffery, Jorge Lopez, Garth Bissette, Howard P. Roffwarg Rapid eye movement sleep deprivation in post-critical period,
adolescent rats alters the balance between inhibitory and excitatory
mechanisms in visual cortex. Neurosci. Lett. 393 (2006) 131–135
Figure 3 - Recordings of fEPSPs in layers II/III of the visual cortex upon stimulating the white matter before (1) and after (2) tetanic stimulation in
control rats (black) and rats deprived of REM sleep (blue) at 5 weeks of age.
16 eurj – fall 2010
The Unique Paths of Isaac Newton
and G.W. Leibniz to the Calculus,
With Shared yet Underappreciated Influence
from Thomas Hobbes
faculty mentor:
Dr. Michele Benzi is a full professor in the Department of Mathematics and Computer Science. A native of Italy, he is a graduate of the University of Bologna and holds a
PhD in Mathematics from North Carolina State University. His main research areas are
numerical analysis and scientific computing. He is the recipient of several research grants
from the National Science Foundation and serves on the editorial boards of some of the
leading applied mathematics journals.
faculty mentor:
Dr. Ursula Goldenbaum is an associate professor in the Department of Philosophy.
A native of Germany, she received her PhD from the Academy of Sciences of the GDR
and an Habilitation from the Technical University of Berlin. Her scholarly interests include the History of Philosophy in the 17th and 18th Century and the European Enlightenment. A former member of the Institute for Advanced Studies at Princeton, she
serves on the board of several societies for the history of philosophy.
Elizabeth Rogawski
‘10 C
Liz Rogawski recently graduated from Emory College
with degrees in Biology
and Chemistry. She has also
completed the Mathematics
minor and is interested in
integrating math with her
studies of human health and
disease. This fall, she plans
to attend UNC Gillings
School of Public Health for
graduate work in epidemiology.
A
midst the whirlwind of advances made in mathematics
by a variety of geometers and philosophers in the seventeenth century, Isaac Newton (1642-1727) and Gottfried
Wilhelm Leibniz (1646-1716) are distinguished from
their contemporaries in both creating firm principles for the new
field of calculus. Based in the new scientific methods developed
by their predecessors, such as Galileo and Descartes, this new discipline expanded and quickly grew in popularity due to its succinct
nature and relevance to a broad array of problems. While Cavalieri,
Torricelli, Kepler, Wallis, Fermat, and others developed many basic concepts and several techniques that contributed to its formation, Newton and Leibniz alone deserve to be named the creators
of the calculus for their discoveries. At their time, mathematicians
were focused on problems concerning the properties of curves, such
as maxima, minima, and tangents. Also, problems of quadratures
and cubatures continued to command attention at this time. With
the concepts of indivisibles and infinitely small quantities, scientists were able to solve many problems previously considered insurmountable. These developments in mathematics were also relevant
for more fully understanding the predominant physical unknowns
of the era pertaining to astronomy and mechanics. In particular,
infinite series, infinite products, and logarithms provided new tools
for mathematicians to expand the breadth of science, and these
techniques became extensively valuable for mathematicians across
the continent.
The contributions of Newton and Leibniz irreversibly reshaped
the study of mathematics through their introduction of the calculus, which is taught using the same basic principles even today.
Without their development of specific rules and techniques, calculus would lack the power it wields today to solve an incredible range
of complex problems. First, the reasons for distinguishing Newton and Leibniz from their contemporaries as the creators of the
calculus will be discussed, emphasizing how their accomplishments
advanced beyond those of other great mathematicians of their time.
The methods of the two men will then be analyzed critically to
distinguish between their respective approaches to calculus. This
discussion will include a reasoned hypothesis demonstrating widely
underestimated influence from the philosopher Thomas Hobbes
(1588-1679) on these mathematicians and the subsequent consequences for their mathematical research.
To demonstrate the novelty of Newton’s and Leibniz’s discoveries, one must first mention the advances made by their immediate
predecessors. Johannes Kepler, though most famous for his three
laws of planetary motion, is also known for the use of indivisibles to
find areas and volumes of solids of revolutions (Grattan-Guinness
207). For example, he calculates the area of a circle by summing
the areas of infinitesimal triangles with heights equal to the radius
of the circle. For more complicated problems such as calculating
the area of an ellipse, Kepler computes the ratio of two known areas
and determines the proportion between them. While this method
of using ratios solves a variety of problems successfully, it requires
initial understanding of the geometrical dimensions of the problem,
preventing it from serving as a universal technique. Bonaventura
Cavalieri, a student of Galileo, also makes important contributions
to the “pre-calculus” through his calculation of areas by means of
indivisible quantities. He and Pierre de Fermat independently determine the area under a parabola and extrapolate this integration
to all functions of the form, y = xn where n is an integer. However, this method is also limited, as Cavalieri only wishes to handle
curves that have “a friendly shape” (Grattan-Guinness 227).
18 eurj – fall 2010
Cavalieri’s colleague, Evangelista Torricelli, extends the established rule of integration for y = xn to include the case in which
= m / n or is even negative. He also works with lengths of transcendental curves, such as spirals, and demonstrates that the solid
of revolution known as Gabriel’s Horn has an infinite surface area,
but finite volume (Grattan-Guinness 227). John Wallis is known
for the summation of infinite series by his method of arithmetic integration. In providing a formula for 4/π, Wallis applies a notion
similar to the limit in describing his process, “it may be done as far
as one likes until the difference between the greater and the smaller becomes less than any assigned quantity” (Wallis 166). Finally,
Pierre de Fermat succeeds in finding centers of gravity for solids,
maxima and minima of curves, and tangents of polynomials (Fermat 340). Each of these advances contributes to a growing base for
the calculus to come. However, their methods using indivisibles are
criticized as being non-rigorous and are met with much resistance,
especially from Hobbes. These scientists together do not yet produce a general knowledge for the calculus, but clearly pave the way
for the broad synthesis by Newton and Leibniz.
Newton and Leibniz independently establish universal rules
for the calculus, earning the status of the creators of this new field
in mathematics. Instead of approaching specific problems as distinct, both men seek to develop a method for the calculus that is
applicable to all problems. The major insight of both men concerns
the concept that differentiation is the inverse process of integration
(Grattan-Guinness 246). Newton asserts that given any right lines
or curves, he can find areas and volumes, and conversely from any
areas or volumes, he can find the curves (Newton 366). In his letter
to Henry Oldenburg in October of 1676, Newton cleverly hides
his revelation in an anagram, which translates to the dogma that
when given derivatives, one can find the function (Newton 367).
This notion today is essentially equivalent to the fundamental theorem of calculus and serves as the basis for the introductory study of
calculus. In fact, Newton further demonstrates understanding of
the relationship between derivatives and anti-derivatives by noticing that finding the fluent from the fluxion (i.e. the function from
its derivative) is a much more difficult problem than the opposite
(Newton 378). Similarly, Leibniz recognizes the inverse nature of
tangents and quadratures, showing “that the general problem of
quadratures can be reduced to the finding of a line that has a given
law of tangency” (Leibniz 354). In this way, Newton and Leibniz
integrate the language of algebra and variables with calculus and
its geometrical applications. Functions obtained from processes of
differentiation can be further manipulated through integration and
vice versa (Grattan-Guinness 246).
Another major achievement for Newton and Leibniz in creating the calculus is their ability to handle functions previously avoided or neglected by mathematicians. Most of their predecessors only
dealt with simple functions, shying away from transcendental functions, irrational quantities, and even fractions. For example, for
Fermat to apply his method, he had to spend substantial effort in
first converting the problem entirely to one involving only polynomials. By contrast, Newton and Leibniz extend their methods to
include these functions and in their publications show they are fully
aware of this power of their techniques. In explaining his differential calculus, Leibniz notes the universality of his method, “all other
differential equations can be solved by a common method. We can
find maxima and minima as well as tangents without the necessity
of removing fractions, irrationals, and other restrictions” (Leibniz
350). Newton boasts that his method is the single general way to
solve problems of differentiation, “Nobody…could draw tangents
any other way, unless he were deliberately wandering from the
straight path” (Newton 366), and Leibniz echoes this sentiment,
“pertaining to even the most difficult and most beautiful problems
of applied mathematics…without our differential calculus…no one
could attack with any such ease” (Leibniz 352). In this way, Newton and Leibniz are aware that they are the first to create general
methods for the calculus that are straightforward, concise, and apply to all problems previously considered as unrelated questions by
their contemporaries.
With the ability to solve a wide range of problems, Newton
and Leibniz don their new calculus with universal rules and terminology to be applied to all dimensions of the new discipline. This
understanding of the need to synthesize the calculus into distinct
rules is absent from their predecessors. Both Newton and Leibniz
develop their own terminology for the basic concepts of the calculus—for Newton, fluxions and fluents (Newton 376), and for Leibniz, differentials and sums, later called integrals (Grattan-Guinness
245). They also both develop rules for calculus that could be generally applied to a broad range of functions. For example, Leibniz
outlines the properties of derivatives with respect to addition and
subtraction, and describes among others, the product and quotient
rules for differentiation (Leibniz 349). Newton proposes how to
find the fluxion of x that is applicable for all (Newton 378).
While Newton and Leibniz use these rules to solve problems rapidly in a few lines, their predecessors were required to labor intensely
over each problem individually. The similar accomplishments of
Newton and Leibniz clearly distinguish them from their contemporaries as the creators of the calculus, owing to their insights into the
processes of calculus and their development of methods that apply
in full generality.
However, while Newton and Leibniz may be paired together
as the creators of the calculus, they approach this new field in very
different ways. One of the most fundamental differences between
their respective approaches to calculus is the way in which the men
generate their methods and that which provides the basis for their
discoveries. Newton develops his calculus through use of the binomial theorem and other series (Grattan-Guinness 247). In fact,
infinite series are an integral part of his calculus. Newton’s method
consisted of expanding functions into power series and then differentiating or integrating each term of the expansion. For example,
he develops the derivative of x through manipulations of the binomial series expansion of (x + o ) , where o stands for an arbitrarily small quantity. To differentiate or integrate transcendental
functions, Newton expands them into power series first and then
applies his formula for x to each term (Grattan-Guinness 243). In
contrast, Leibniz bases his approach in algebraic techniques and especially the ratio of differences, although his method is rooted in
geometry (Grattan-Guinness 247). He relies on the inverse relationship between addition and subtraction, and multiplication and
division, to describe similar operations in calculus. He considers
dx, dy, etc. to be small differences and works heavily with the ratios
between these differences, dx:dy (Leibniz 351). Leibniz also finds
tangents differently from Newton by systematically using the characteristic triangle (Grattan-Guinness 245). Contrary to speculations at the time which led to a notorious controversy over priority,
the difference in the origins of Newton’s and Leibniz’s methods provides convincing proof that they were formed independently (Hall,
Philosophers 1).
Perhaps the most obvious difference between the two meth-
ods is in their notations. Although terminology may appear trivial,
Leibniz’s notation is much more convenient than Newton’s, and allowed his followers to be more successful than Newton’s in expanding the new calculus. Newton denotes fluxions, his derivative concept, as , , etc. and fluents, his integral or antiderivative concept,
as x, ỳ, etc. Higher order derivatives and integrals require multiple
dots and slashes, resulting in a tedious and even impractical notation for derivatives of high degree (Newton 378). The small increments he introduces, o, are thought of as moments of time. He describes oż, o , and o as, “the momentaneous synchronal increment
of the quantities z, y, x” (Newton 379). On the other hand, Leibniz
notates with differential increments, dx, and sums, ∫y (later ∫ydx),
in which ‘d’ and ‘∫’ are inverse operators. In this case, the derivative is the ratio of differentials, dx:dy and the integral is the sum of
y ∙ dx, denoted ∫ydx (Grattan-Guinness 245). By introducing this
notation, Leibniz is able to clearly show the inverse relationship between differentiation and integration. The fundamental theorem of
calculus is in fact reflected in his notation, d∫y = ∫dy = y. The chain
rule is also immediately evident using Leibniz’s notation of ratios of
differentials, and he is able to provide an obvious explanation for
higher order derivatives by performing algebraic operations on these
ratios. Leibniz’s notation continues to be valued over that of Newton in its utility and is still used today in the study of calculus.
Both Newton and Leibniz are forced to handle infinitesimal
quantities when developing their methods. Newton’s evolving calculus first relies heavily on infinitesimals, as moments of time, o.
Aware of the criticism that infinitesimals are paradoxical and result
in non-rigorous demonstrations, Newton later scrupulously attempts to eliminate any reference to infinitesimal quantities in his
calculus. He instead introduces the notion of the limit, whereupon
he defines “evanescent divisible quantities” (Newton 373). He considers quantities and ratios which “in any finite time…approach
nearer to each other than by any given difference” (Newton 368).
In this way, Newton is highly concerned with making his method
more rigorous by replacing infinitesimals with limits. In contrast,
Leibniz simply shies away from considering his differentials, dx,
as infinitesimal, characterizing them only as small increments that
can be divided. He justifies the use of these inconsistent quantities through analogy with imaginary numbers. Both imaginary
numbers and infinitesimals appear in intermediate calculations, but
because they are eliminated in the end result, these quantities are
acceptable and do not lead to contradictions. Comparably, Newton
and Leibniz disregard higher-order infinitesimals, such as dxdy, as
negligible in the intermediate steps of calculations (Grattan-Guinness 246). In this way, both men are aware of the issues with infinitesimals, and they attempt to circumvent these criticisms in various
ways.
Although his role has been largely overlooked by scholars, considerable evidence suggests that Thomas Hobbes was influential
for both Newton and Leibniz in their developments of the calculus. While not generally celebrated as a mathematician himself,
Hobbes affects the mathematics of these two men in significant
ways. Hobbes promotes a mechanical philosophy in which science
explains effects with one efficient cause, local motion. Hence, he
considers all of nature as bodies in motion. For example, a line is
the trace of a moving body for Hobbes, and a surface is produced
by the movement of a line. Because the motions of bodies are understood in terms of space and time, velocity and time enter into
geometry as variables. Newton studied Hobbes’s De Corpore while
an undergraduate at Cambridge (Hall, Isaac 402) and was consefall 2010 – eurj
19
quently exposed to Hobbes’ understanding of curves in terms of
kinematics (Arthur 8) and his discussions of conatus and impetus.
Conatus can be thought of as instantaneous or point motion, and
impetus as instantaneous velocity, defined as the limit of the ratio
∆s/∆t with ∆t 0 (in modern notation). This importance of time,
motion, and velocity is clearly influential in the development of
Newton’s calculus. For Newton, quantities are variable with time,
resulting in a kinematic representation of curves and the naming of
geometrical quantities as “fluents,” which suggests movement and
reflects Hobbes’ notion of conatus. Newton consistently uses the
chain rule to differentiate with respect to time, and the connection
with Hobbes can be applied here as well. Newton’s consideration
of velocities as “fluxions” and accelerations as “fluxions of fluxions”
appear to be closely related to Hobbes’ concept of impetus. In addition, Newton’s infinitesimal concept, o, he names a moment, or an
instant in time. These dimensions of Newton’s calculus show signs
of Hobbes’ emphasis on moving bodies to describe problems in geometry.
Leibniz’s first exposure to the study of math is through
Hobbes, in reading Leviathan, De homine, De Corpore, and other
works. However, these formative studies have been ignored by
many scholars due to Hobbes’ poor reputation as a mathematician
(Goldenbaum 55). By reading Hobbes’ Opera philosophica, Leibniz learns the mathematics of indivisibles and a broader history of
mathematics through the work of other mathematicians from Archimedes to Cavalieri (Goldenbaum 68). He in fact continues to
study mathematics with hopes to understand Hobbes’ philosophy
of the conatus and point motion, which stems from his interest in
uncovering the philosophy of the mind (Goldenbaum 61). Leibniz
develops his own philosophy to explain nature as part of his critique
of Hobbes’ mechanical philosophy (Goldenbaum 62). In this way,
Hobbes serves to entice Leibniz to further his study of mathematics. After this unique introduction to the field, Leibniz’s mathematics is further molded by several of Hobbes’ perspectives, including
his views on infinitesimals, the principle of continuity, and the relativity of hardness and softness of bodies (Goldenbaum 72-73).
Hobbes is deeply concerned with the paradox of infinitesimals
and criticizes John Wallis for lack of justification in their use. He
refuses to consider infinity as a quantity, and introduces conatus as
an alternate infinitesimal concept that describes motion through
a space and time smaller than any considered, but not infinitely
small. Through reading Hobbes’ critiques of Wallis, both Newton
and Leibniz become conscious of the theoretical problems of employing infinitesimals in their mathematics. Newton attempts to
eliminate any reference to infinitesimals in introducing a concept
similar to the limit. He aligns with Hobbes in asserting, “there is
no necessity of introducing figures infinitely small into geometry”
(Newton 378). Similarly, instead of considering his differentials
as infinitesimal, Leibniz mentions only that they are differences
and focuses on the ratio between these differences. In this way, he
avoids infinite numbers by considering them as merely indefinite
(Goldenbaum 69). In alliance with Hobbes, Leibniz is “reluctant
to adopt such contradictory ideas as “infinite quantities”…from
the very beginning” (Goldenbaum 76). The sensitivity to the nonrigorous nature of employing infinitesimals in their methods of calculus is clearly heightened by Hobbes’ philosophy and critiques of
Wallis.
Both Newton and Leibniz succeed in extending the study of
mathematics far beyond their contemporaries, earning them the
titles, the creators of the calculus. While other mathematicians of
20 eurj – fall 2010
the time could only solve isolated problems burdened by a variety
of caveats, Newton and Leibniz develop methods that can handle
all problems of calculus with a language and fundamental theorem that is widely applicable. Despite Newton’s vicious attacks on
Leibniz in the priority dispute over who first created the calculus,
scholars have agreed that their methods were developed independently (Hall, Philosophers 1). Priority cannot simply be determined
from the chronology of the publication of their works because while
Leibniz published “A New Method for Maxima and Minima as
Well as Tangents, Which is Impeded Neither by Fractional nor by
Irrational Quantities, and a Remarkable Type of Calculus for This”
in 1684, he had previously outlined his method in a letter to Newton in 1677. Although they clearly learned of each others’ progress through correspondence before their publications, there is little
evidence to support Newton’s vicious claims of plagiarism (Hall,
Philosophers xi-xii). This conclusion is supported by their clearly
dissimilar approaches to the calculus, proving that Leibniz’s ideas
were his own. The motivations, techniques, and notations of their
respective methods differ in many respects. However, they do both
allude to the same concepts and are similarly influenced by other
thinkers of the time such as Hobbes. While the story of the invention of the calculus is largely well-known, the role of Hobbes has
just recently been explored and is emphasized here as a vital component in its creation. Newton and Leibniz deserve to be widely
celebrated together for their contributions to the calculus, and at
the same time, the influence of Hobbes merits significantly greater
appreciation than has been accorded by historians in the past.
Works Cited
Arthur, Richard T.W. “Leary Bedfellows: Newton and Leibniz on the Status of Infinitesimals.” Infinitesimal Differences: Controversies between Leibniz and his
Contemporaries. Eds. Ursula Goldenbaum and Douglas Jesseph. New York:
Walter de Gruyter, 2008.
Fermat, Pierre. “From ‘On a Method for the Evaluation of Maxima and Minima.’”
Trans. Dirk J. Struik. Classics of Mathematics. Ed. Ronald Calinger. Oak
Park, IL: Moore Publishing Company, 1982. 339-342.
Goldenbaum, Ursula. “Indivisibilia Vera – How Leibniz Came to Love Mathematics.” Infinitesimal Differences: Controversies between Leibniz and his Contemporaries. Ed. Ursula Goldenbaum and Douglas Jesseph. New York: Walter de Gruyter, 2008.
Grattan-Guinness, Ivor. The Rainbow of Mathematics: A History of the Mathematical Sciences. New York: W.W. Norton & Co., 1997.
Hall, A. Rupert. Isaac Newton, Adventurer in Thought. Oxford, UK: Blackwell,
1992
---. Philosophers at War: The Quarrel Between Newton and Leibniz. New York:
Cambridge UP, 1980.
Leibniz, Gottfried Wilhelm. “From ‘A New Method for Maxima and Minima as
Well as Tangents, Which is Impeded Neither by Fractional nor by Irrational
Quantities, and a Remarkable Type of Calculus for This’ (1684)” and “From
‘Supplementum geometriae dimensoriae…’ in Acta Eruditorum (1693).”
Trans. Dirk J. Struik. Classics of Mathematics. Ed. Ronald Calinger. Oak
Park, IL: Moore Publishing Company, 1982. 348-356.
Newton, Isaac. “From a Letter to Henry Oldenburg on a General Method for Finding Quadratures (October 24, 1676)” Trans. H. W. Turnbull, “From Principia Mathematica (1687)” Trans. Andrew Motte, Rev. Florian Cajori, and
“From the Introduction to the Tractatus de quadratura curvarum (1704)”
Trans. J. Stewart. Classics of Mathematics. Ed. Ronald Calinger. Oak Park,
IL: Moore Publishing Company, 1982. 361-380.
Wallis, John. The Arithmetic of Infinitesimals: John Wallis (1656). Trans. Jaqueline
A. Stedall. New York: Springer-Verlag, 2004.
Can You Get a PhD in Happiness?
By Samyukta Mullangi
An Interview with Corey Keyes, PhD
Corey Keyes, or as he is sometimes better known - Dr. Positive, is an Emory professor of sociology who has been studying social and psychological functioning and “flourishing,” thereby pioneering the new field of positive psychology.
Samyukta: What is your definition of social well-being?
Dr. Keyes: Social well-being is the ability to function well in your
public life, in the specter that goes beyond the household, into the
community, into the workplace, and even into cities and the nation.
When we measure it, we don’t measure it as one thing. It actually
comes in five different aspects or dimensions. So social well-being
consists of a feeling of integration, a sense of contribution, that the
things that you do on a daily basis matter to the world, a sense of
acceptance of other peoples, a sense of social growth – that we are
part of units or groups that go beyond just being individuals and
can grow. We honestly have to believe that groups that we are a part
of, whether it is a state or nation, can grow. And the last one is social coherence, that the world around you, what’s happening in the
society makes sense to you. So there are a lot of different ingredients
that go into social well-being.
What is positive psychology?
Positive sociology or psychology is the study of human strength, resilience, and what might be referred to as protective factors – that’s
a technical term that people use in the study of resilience – the
things that protect you against adversity, and in fact, allow you to
grow even though you may be experiencing adversity. It’s the study
of what it is that makes life worth living, in the shorthand. That
may be, as an individual, what makes you happy, what brings satisfaction in your social life, what brings you a sense of contribution,
or a sense of integration, or simply, what gives your life a purpose,
direction or meaning.
How does it differ from traditional psychology? It seems to have a narrower focus, so are your methods different?
It’s not that our methods are different; we’ve taken all that we’ve
learnt about how to do really good social science but applied it to a
very different set of questions from traditional psychology or sociology. Both fields of psychology and sociology are very interested in
alleviating human suffering, illness, disease, early death –all those
things that we humans want to run away from. The belief is that by
studying why it is that people become ill, we can reverse-engineer
and create healthy people. There is some logic to that when it comes
to biological systems. But when it is applied to psychology and sociology, it fails because health is not merely the absence of bad things.
So studying only why people break down gives you limited information on how to prevent them from breaking down, but it doesn’t
give you information on how to promote health. So I’d actually like
to say that we’re not asking limited questions but that, far from it,
we’re completing the picture. Traditional psychology only asks 50%
of the questions, and that is why people go wrong. We’re asking
the other 50%, completing the picture, that is, what can make life
worth living, what makes life right? I like to think that it’s balancing
it out. Life is both suffering and joy. We’ve studied a lot of suffering,
but we’ve not studied what makes for joyful living.
What is the
losada line?
Technically
speaking, it’s
the
translation
of
non-linear
dynamics
into a simple
formula,
the ratio of
positive to
negative experiences
required for
you to flourish. It’s takfall 2010 – eurj
21
ing in an equation that was developed in non-linear dynamics to
explain chaotic systems that create the butterfly effect – where one
change expands, and why it keeps doing that. When you translate
that into human emotions and positive and negative experiences,
the equation is translated as for every one negative experience you
have, in order to maintain flourishing, you have to have three positive experiences to counteract it. The reason for that is, one-on-one,
bad is always stronger than good. So if it’s one to one, good things
will always lose to bad things in terms of our focus, our concentration, and what we remember. So in order to tip that into healthy
balance, if you have one bad thing, you need at least three or more
good things to have this healthy system that keeps expanding, growing, and staying resilient.
are flourishing. But 80% are free of mental disorder. So we usually
walk around saying, wow 80% free of mental disorder. We’re doing
well. But my research says no. What’s interesting is that more adolescents and kids than adults are flourishing. So 40-50% of American adolescents are flourishing. It goes down by the end of high
school to about 39%, and by the start of young adulthood it’s about
16-20%. It gets better in adulthood up to the age of 74. So the least
likely time in our entire lifespan to flourish is around ages 25 to 45.
Before or after that, rates of flourishing are much higher until the
very end of life. You’re not flourishing in the prime time of your
life. Think about that: why? What is about being a young adult in
American society or most industrialized societies, that the odds are
against your having really good mental health?
Does the magnitude of these events matter?
That’s a good question. They haven’t looked at that yet. But so far,
they haven’t had to, because you just need three things of what
would be considered positive experiences, positive ways of talking to people, positive emotions, for every one of their corollaries.
Intensity doesn’t matter, so far. But that’s a good question. To balance one slightly negative thing, do you only need two really really good things, rather than just three? In terms of quality, if those
two things are really good, you don’t need that third. But no, they
haven’t looked at that.
What would you say about the mental health of the Emory student population? Is it better or worse than other campuses?
We’re actually studying that – there’s a study out there called “The
Healthy Mind” study. Emory participated in it in 2007 and we’re
going to participate again next year. In the first year, we had 12 other campuses. On a mental illness side, Emory was among the worst.
But what’s interesting is that, when you looked at the positive end,
we were among the highest as well. So we have a very bifurcated
distribution of students. There’s very little in between – either you’re
doing really well, or you’re doing really poorly. So we were the top
in both categories. There were high levels of mental illness and
above 50% of Emory students were flourishing.
What are the implications of your findings on society, governmental
policy, and educational systems?
I’ve been thinking a lot about this because I’m now often invited
to talk to the governmental officials who are interested in public
health, particularly mental illness in the population. It turns out
that we’ve only recently discovered that mental illness is a really serious public health issue. So everyone agrees on that but they don’t
know how to stem the tide of rising mental illness. In most countries, the treatment of illness is the way they go about that because
we’ve been focusing on getting treatments, pills and therapies. The
implication of my research is clear that you could treat everyone
and you could cure every known mental illness, and you would
still not necessarily have a mentally healthy population. The treatment of mental illness is only half the battle. And in fact, because
mental health is more than the absence of mental illness, anything
less than flourishing results in all kinds of losses – missed days of
work, healthcare costs go up, resilience goes down, a whole host of
problems that you need to be both promoting and preventing at the
same time. You need to treat and protect. Treat mental illness and
protect good mental health in the population at the same time. And
in fact, we’re finding that if you want to prevent mental illness, promote flourishing. If you really want to reduce rates of mental illness
in a population, don’t focus on cures and treatments. Start promoting the things that go into flourishing.
Are Americans in general susceptible to not flourishing? I feel like psychological problems seem primarily a western hazard.
Yeah. In fact, I have a colleague in Australia who’s gone so far as to
say, is our culture a health hazard? Because any country that goes
through the industrialization phase, the post-industrialization phase
moves into a market-dominated culture where everything is monetized, right down to your time. Time is money. So how do you
spend your time? When you look at the rates of mental illness by
country, the U.S. eclipses most countries developed and developing
nations. And so, here’s the bad news: only 20% of American adults
22 eurj – fall 2010
But sometimes, I wonder, what came first, the chicken or the egg? So
if, for instance, people are dissatisfied with their college experience, is it
because they already had a mental illness or did the terrible experience
cause them to become depressed?
Well we can’t say for sure right now, but we’re actually putting in a
proposal to do a study where we can untangle that. There is usually
a lot of research on college students. But when it comes to whether
college is good or bad for your mental health, there’s been very little
to none. We do cross-sectional research that just looks at the rates
of mental illness but we can’t discern whether college is the cause of
this problem or it’s just that more mentally ill students are showing
up and that the mental illness undermines their college experience.
I suspect it can go both ways. But we’re going to see if we can get
support to do a longitudinal study here at Emory, Boston College,
and two other campuses to get an answer to that question. And our
hope is that more students leave flourishing than when they entered. A good liberal arts college experience should elevate students,
that is, raise their levels of flourishing. You should leave here feeling a greater sense of purpose in life, a sense that what you can do
now is of value to the world, that you are a part of our society, that
you have something important to say, that you have autonomy, that
you’re accepting of other people, and not just yourself. What else
is a great education? It’s not just about grades; it’s about elevating,
flourishing. So my hope is that it doesn’t undermine flourishing,
that it increases it.
There was a story on CNN yesterday, that they found a pill to cure alcoholism at Brown. What would you have to say about that? Do you
think that a pill can create happiness? The whole reason that the pill
was able to work, really, was because it mimicked those feelings of euphoria even without taking a drink. So for instance, what are your feelings on antidepressants?
Well I think there is a place for those drugs. I feel as though their
territory, though, has overmedicalized the domain of mental illness.
I mean when we do these big studies in the American population,
we don’t differentiate between people who fit the criteria for depression but who are experiencing things that that would be a normal
reaction to, like getting laid off or having just experienced a major
trauma in their city. For instance, where was it that a gunman went
into a church and shot a bunch of people? That community should
react appropriately in a way that’s reflective of mental illness, but
we shouldn’t call that mental illness. In treating the situation, we
should support them, provide them with therapies that are more
socio-culturally sensitive but the problem isn’t with the individual;
the problem is with society. We mix that up with what we would really call mental illness, which is an unexpected reaction to a normal
situation. In that regard, I think all those drugs have been pushed
too hard as the only solutions to the problems. We try to fix individuals and not the crappy social situations that persist in our
world. We’ve got to stop that, because otherwise, we’re all going to
end up as overmedicated and a very sick society. Somebody will be
very wealthy because they’ll make a lot of money off of us. That’s
what disappoints me. There’s too much money in it. So good for
Brown, I’m sure that they’ll make a lot of money off that patent
and spread it around. And that’s at the expense of a lot of people
who we could have prevented from becoming alcoholics in the first
place. And that’s what bothers me – this medicalization. You just
wait for people to get sick and here, I got something. Give me some
money for what I’ve got for you. That’s ethically disgusting, if you
ask me.
So back to flourishing: it can be applied to little kids? We’re not allowed
to drink until we’re 21, we’re not allowed to smoke until we’re 18. These
decisions, people say, young adults are incapable of making. So can you
look at kids and think, do they have a purpose in life, do they feel integrated?
Yes! Oh goodness yes! And in fact, we don’t know if it goes earlier
than the age of 12 but between the ages of 12 and 18, all of the
things we were thinking were signs and symptoms of good mental
health in adults apply to adolescents. So by middle school, kids are
already thinking about, does my life have a direction or meaning to
it? That’s important in and of itself because we used to think that
it only mattered whether they were happy. Smiling. No, kids are
thinking, do I belong somewhere? Do I fit in? Is it okay to speak
my mind? Am I accepting of all other people, am I loved? Am I
integrating, contributing? All those things. And what’s ironic is that
I think while we’re all focused on helping kids only develop – we’re
really committed to that – they’re doing better than adults. The big
risk factor is actually growing up. To become an adult in America?
25-45. When you’re starting a job, starting a family, trying to raise
a family – you’re on your own. Chances are, it’s going to undermine
what goes into your mental health. And that strikes me as a sad
message.
What’s your take on the whole nature vs. nurture debate? Do you think
people may be just intrinsically happy, motivated, and positive? Have
you looked at that?
Well we do have the capability to look into our data and I’ve looked
at the genetics in a very crude manner, and I can tell you roughly,
that the broad heritability of flourishing is roughly 60% in the population. That’s no higher or lower than mood disorders, especially
depression. And this coincides with studies about specific forms of
happiness that they’ve done at the University of Minnesota. It’s her-
itable. But here’s what we’re finding: the whole nature/nurture debate is a false dichotomy. They act and interact together. The greatest example of that is in the new field of epigenetics. “Epi” means
just above the genome. So there’s a level of the genome that operates
above our basic DNA. Sure we inherit a lot of pieces of DNA. Of
that, maybe 20,000 code for what really makes us human beings.
Of that 20, not all of those pieces are on all of the time. And that’s
a good thing. Because we’ve all inherited risks. But as long as they
stay off, we’re not affected. The epigenome is the layer that switches
things on and off at the DNA level. The epigenome is responsive to
your environment. So think of it this way: you can have environmental experiences that are passed on to you from your mom and
dad, or your great-grandparents, all the way down, whether they
were exposed to poverty, whether they had long periods of hunger
or deprivation. That would have switched on and off pieces of your
DNA through the epigenome. You inherit both the DNA and the
epigenome – the switches.
So if the giraffe stretches its neck, you get a longer neck?
Yeah, if there were conditions under which it was forced to do that.
Nothing in the DNA was changed except for that it was turned on,
or something was turned off. Then that whole system gets passed
on. What I’m getting at is that there’s a programmer, there’s a piece
of software, and there’s hardware. It turns out that the DNA is the
hardware, but it doesn’t know what to do without the software,
that’s the epigenome. And the programmer is our environment. Exposure – everything from what we eat, what we smoke, whether our
parents were exposed to food shortages, whether they experienced
an event like 9/11, a major war or trauma – those get passed on
along with the DNA suggesting that environment and genetics are
inseparable and that we have a lot more in control of our DNA
than we ever thought.
Is this a recent discovery?
Yeah. It’s relatively recent, it’s a radical new field, but there are all
kinds of studies now. Mothers who were exposed to 9/11 – the closer they were to 9/11, the more their infants were at risk for having
sort of PTSD-like conditions as they grow up. And the rat studies
show that if they’re raised to be very sensitive to the environment,
because their mothers experienced something that says to the developing fetus, I live in a hostile world, so you come out sensitive.
It’s very adaptive but if it were true, we don’t live in a world where
there’s constant … so that will get passed on until we intervene. We
can intervene and shape the epigenome so that it switches off that
sensitivity and that’s what’s remarkable. That doesn’t require pills;
that requires things like yoga, compassion, creating contemplative
places for people to be calm, developing skills and regulating your
emotions. So it’s amazing, the more we learn about how our biology
works, the more we learn about how important our environment
we really is, and how much we are in charge of it. I think that’s
phenomenal.
That was a good interview. Thank you!
[laughs]
Recent Emory graduate Samyukta Mullangi
double-majored in biology and creative writing, and served as one of the past co-editorsin-chief of EURJ.
fall 2010 – eurj
23
Introduction
A Neurological and Theoretical
Review of Metaphor
Comprehension
Alexandra Kreps
‘09 C
abstract
This review surveys conflicting neurological and linguistic theories of metaphor
comprehension in an attempt to elucidate how metaphors are used, processed and understood. First, it provides a review of the definition of a metaphor and its various subcategories. It will explore the general theories of metaphor comprehension, highlighting
non-scientific approaches to metaphor analysis. Secondly, several studies are presented
to analyze the neurological processing of literal and figurative language. fMRI, PET, and
ERP were utilized to garner data on brain activation in various areas tied to language
comprehension. Many studies employed patients with neurological disorders such as Alzheimer’s disease and autism, as well as right-brain damaged subjects, to pinpoint areas
and circuits in the brain necessary for language comprehension. Furthermore, this review
highlights studies exploring the ability of metaphors isolated to a single modality to activate sensory-specific brain regions, indicating future avenues of research.
faculty mentors:
Krish Sathian, MD, PhD, is Professor of Neurology, Rehabilitation Medicine, and
Psychology, and Director of the Neurorehabilitation Program in the Department of Neurology at Emory University; he is also the Medical Director for Emory University’s Center for Systems Imaging.
Simon Lacey, PhD, is a Research Associate in the Department of Neurology.
key terms:
Metaphor - a figure of speech in which a phrase or word denoting an object or idea replaces another to suggest parallelism between them
Conventional Metaphor - a metaphor used in everyday language, quickly recognized by
fluent speakers
Novel/Unconventional Metaphor - a metaphor less commonly used or heard, but generally more creative and/or original; meaning less apparent or easily processed
Theory of the Conceptual Metaphor - a theory suggesting that human physical sensory
experiences shape metaphor creation, use, and understanding
Graded Salience Hypothesis - supports the notion that the comprehension of a metaphor is contingent upon its saliency
Semantics - the study of meaning in language
Direct Theory - the activation of the metaphorical and literal meaning of a sentence occurs simultaneously
Indirect Theory - the literal meaning of a sentence is first understood and subsequently
stimulates the processing of the metaphorical meaning
Contextual Theory - a metaphor’s meaning will be initially understood through its context
Pragmatics - an area of linguistics that focuses on the importance of context in understanding meaning
Alexandra Kreps recently
graduated from Emory with
a B.S. in Neuroscience and
Behavioral Biology. She currently resides in New York
and works at a Transcranial
Magnetic Stimulation treatment center in Lenox Hill
Hospital, providing a new
therapy for depression. Her
hobbies include drawing,
painting and art history.
Metaphors are considered an essential part of language. They
are vital to self expression because of their ability to communicate
ideas beyond their literal meaning. The importance of metaphor
comprehension goes beyond simply understanding a metaphor’s
literal meaning. Being able to understand a metaphor most likely
implies a strong and solid grasp on the uses of non-literal language.
This review aims to explore the theories behind metaphor comprehension through both a linguistic and biological perspective. The
paper will outline what a metaphor is and how it has been defined,
used and subdivided. Subsequently, this article will explore the
general theories of metaphor comprehension, laying out the nonscientific approach to understanding how metaphors come to be
understood. Lastly, this review will highlight the biological view of
metaphor comprehension, underlining the search to attribute certain brain areas to metaphor comprehension.
Metaphors stem from the way we view our everyday world, the
way we interact with our environment, and how different experiences may evoke similar feelings, memories, and/or emotions. The
overall struggle lies in the simple concept of the conceptual metaphor theory. This theory implies that human experience and mental
capacity may be the limiting factor as to how well a metaphor may
be understood. It describes how metaphors may create metaphorical mappings in the brain because they are “pervasive in everyday
life, not just in language but in thought and action” (Lakoff and
Johnson, 1980, p. 3). The processing of a metaphor requires the
comprehension of a certain conceptual domain in terms of another
by its coherent organization in the brain. Thus, many argue that a
metaphor may be understood simply because of its frequent usage,
rather than the understanding of its contextual relevance. This debate drives much of the innovative research in the field of metaphor
comprehension.
The formal definition states that a metaphor is a figure of
speech in which a phrase or word denoting an object or idea replaces another to suggest parallelism between them (Merriam-Webster,
2003). It may also be viewed more simply as the comprehension of
one thing in terms of another (Howe, 2008). Shibata, Abe, Terao,
and Miyamoto (2007, p. 92) argue that the understanding of a
metaphor is “achieved by the complex interaction of topic and vehicle word meanings”. The topic is the main subject which is then implicitly compared to the vehicle (Fass, 1986). For example, “The car
drank gasoline” (Fass, 1986, p. 341). Within this phrase, the topic
is the car, and the vehicle is the concept of an animal. This view
of metaphor comprehension highlights that metaphors are implicit
comparisons which come about the interaction and relationship of
two concepts. It equates two different concepts, creating a relationship that is not necessarily apparent. Thus, it may be categorized as
a rhetorical trope, a figure of speech that uses words or phrases in a
manner not usually intended.
Similes are a commonly used example for comparison where
the main difference lies in the use of phrases such as “is like” or
“is as”. By requiring that these words be inserted between the two
objects or actions in question, a simile draws direct or explicit comparison. In contrast, a metaphor is implicit, prohibiting “like” or
“as” to link the two ideas. Additionally, a simile is a comparison of
two ideas that are not seemingly related but resemble each other in
at least one facet, whereas a metaphor more often suggests several
similar qualities between two very distinct concepts.
Not only are there linguistic tools similar to those of metaphors, but within metaphors, there are several subcategories. Two of
the more common ways are as conventional or novel. A conventional metaphor is used in everyday language and is quickly recognized
by fluent speakers. Lakoff and Johnson (1980, p. 4) define a conventional metaphor as one in which a “concept is understood and
expressed in terms of another structured, sharply defined concept”.
In contrast, novel, unconventional metaphors are less commonly
used or heard, but generally more creative and original. Their meaning is often less apparent or easily processed. Thus, metaphors may
be distinguished by their use or lack of in everyday language, and
this may contribute to the ability to understand its meaning.
Support & Refutation of Conceptual Metaphor Theory
Metaphors create dynamic and expansive opportunities in
which to use language for self expression. There have been several
interesting and often opposing theories as to how this linguistic tool
is processed, as well as how it functions linguistically. Firstly, Lakoff
and Johnson (1980) support the literary power behind metaphors
by using the theory of the conceptual metaphor. The theory suggests that human experience shapes metaphor creation, use, and
understanding. They argue that the concepts within a metaphor
possess uniquely inherent properties. These intrinsic properties relate to physical sensory experiences, thus allowing an individual to
comprehend them. Feldman, Lakoff, and Howell (2000, p.4) highlight this approach with their reference to Lakoff’s “Spatialization
of Form” hypothesis, which implies that a “metaphorical mapping
[is constructed] from the structure of physical space into that of a
conceptual, mental space”.
Lakoff and Johnson (1980) specifically explore the use of conventional metaphors. An example of such a metaphor used by Lakoff and Johnson (1980) was “Argument is War”. They present the
idea that the concept behind an argument is analogous to a battle.
For example, one may be victorious in an argument just as easily
as in a war. Although not all have experienced war, most have been
involved in an argument and studied the history of wars, and thus
may be able to understand the analogy.
The conceptual metaphor theory is scrutinized for its explanation of how a metaphor is understood and reasoned (Keysar and
Bly, 1999, p. 1563). Although Lakoff and Johnson (1980) develop
a strong argument, many criticize this approach toward metaphor
comprehension. Keysar and Bly (1999) argue, and others previously, that “while conceptual metaphors provide convenient means of
expression, they do not constitute means of thinking” (Keysar and
Bly, 1999, p. 1563). In the previous example, Lakoff and Johnson
(1980) assume that the concept of war is well grasped by all. As
Keysar and Bly (1999) argue, this may prove problematic and detract from the understanding of the metaphor because most have
never fought in a war. They believe that having actually fought in a
war is irreplaceable. Therefore, without participating in war, a thorough and strong connection between the themes of argument and
war could not be made.
Gregory L. Murphy (1997) also attempts to refute the legitimacy of the conceptual metaphor theory. He believes that ideas behind metaphor representation have not been sufficiently supported.
One piece of evidence behind his reasoning is that there is a lack of
nonmetaphoric hypothesis represented. Thus, there is no means for
comparison to contrast ideas of how a metaphor must be processed
differently than other phrase types. Murphy (1997) also highlights
that this theory lacks biological support as it was developed by exfall 2010 – eurj
25
perimental psychologists. Murphy (1997) therefore calls for a thorough definition of a metaphoric concept and “how it operates in
any given task” (Murphy, 1997, p. 102). Murphy (1997) also argues
that the concept behind a word may not be easily definable. Using
the word “love”, Murphy (1997) supports the notion of polysemy
(a word having several meanings and definitions to each individual). In turn, Murphy (1997) refutes the conceptual metaphor theory because of the variability of each human’s experience with a word
and the meaning they attach to it.
Lastly, the Graded Salience Hypothesis (GSH) also rejects the
conceptual metaphor theory. It supports the notion that the comprehension of a metaphor is contingent on its saliency (Amanzio,
Geminiani, Leotta, & Cappa, 2008). The degree of saliency is measured by conventionality, frequency, familiarity and prototypicality
(Amanzio et al., 2008). Therefore one may attribute a low degree of
saliency to that of a novel metaphor, whereas a more salient phrase
would be categorized as conventional. Thus, GSH asserts that metaphor comprehension stems from its prominence in semantic language, not the context of the metaphor (Amanzio et al., 2008). Semantics is the study of meaning in communication. GSH implies
that lexical processing, rather than contextual processing, is the primary method of language comprehension. Giora (2004) argues that
“salient meanings are privileged, because they are context resistant”
(p. 93).
Not only are metaphors central to those interested in language and literature, but beginning in the late 1970’s, they became
a topic of exploration for neuropsychologists (Rinaldi, Marangolo,
and Baldassari, 2004). Metaphors, because of their complexity, are
a useful tool to investigate the neural mechanisms underlying language processing. Many theories have been put forward to explain
how a metaphor is understood within the brain, some in support
of the contextual metaphor theory, and others attempting to refute
the strength of the theory. Firstly, the direct theory asserts that the
activation of the metaphorical and literal meaning of a sentence occurs at the same time (Rinaldi et al., 2004). Secondly, the indirect
theory implies that the literal meaning of a sentence is understood
and then used to stimulate the processing of its metaphorical meaning (Rinaldi et al., 2004). Finally, the contextual theory asserts from
a neurological standpoint that a metaphor’s meaning will be initially understood through its context (Rinaldi et al., 2004). Thus,
the metaphorical meaning is understood only if it can be related
to the context of the phrase. Three processes have been employed
in order to analyze metaphors neuroscientifically: positron emission
tomography (PET), event related potentials (ERP), and functional
magnetic resonance imaging (fMRI). These techniques have contributed to a more thorough investigation of the role of the right
and left hemisphere in metaphor processing.
It has been clearly established that the left hemisphere is the
dominant area of the brain involved in language processing and
production for most humans. The left hemisphere system is crucial
for fine-grained semantic analysis of stimuli (Amanzio et al., 2008).
It controls specific language processing including: phonology,
lexical-semantics and syntax (Rinaldi et al., 2004). More recently,
studies have explored the role of the right hemisphere in language
processing, specifically the comprehension of non-salient metaphors
(Amanzio et al., 2008). The right hemisphere is to possess a special
role vital for tasks involving complex linguistic processing, rather
than for its influence on the comprehension of metaphors in gen26 eurj – fall 2010
eral (Amanzio et al., 2008).
To explore the theories of right hemisphere involvement in
metaphor processing, Bottini, Corcoran, Sterzi, Paulesu, Schenone, Scarpa, Frackowiak, and Frith (1994) employed PET. Using
six normal right-handed participants, they studied subjects as they
completed three distinct linguistic tasks: lexical-decisions, the comprehension of novel metaphors and literal sentences. Activation of
both the right and left hemispheres was observed while performing
these tasks. More specifically, they observed how metaphoric language processing activated the right side of the prefrontal cortex,
middle temporal gyrus, posterior cingulate and precuneus. Bottini et al. (1994) concluded that there was “widespread distributed
systems bilaterally with the right hemisphere having a special role
in the appreciation of metaphors” (Bottini et al., 1994, p. 1241).
Bottini et al. (1994) therefore suggest that both hemispheres are involved in metaphor processing, but the right hemisphere may also
enhance one’s ability to comprehend specific metaphoric figurative
language.
Using fMRI, Faust and Mashal (2007) also investigated the
popular theory of right hemisphere activation during metaphor
processing using a semantic judgment task. The research team utilized only novel metaphor expressions from poetry to evaluate the
role of saliency, or lack thereof, in the recruitment of right hemisphere processing in thirteen normal adults participants. This nonsalient language included a stimulus pool of Hebrew phrases. Two
words were placed together and formed either literal (ex: problem
resolution), conventional metaphoric (transparent intention), novel
metaphoric (conscience storm) or an unrelated pair (wisdom wash)
(Faust and Mashal, 2007). Overall, the right hemisphere was able to
more quickly and efficiently decide whether the words in the pair
were related or unrelated, with significant results during the use of
novel metaphoric word pairs. In particular, the right homologue
of Wernicke’s area and the right posterior superior temporal sulcus
were engaged during this specific metaphor processing (Faust and
Mashal, 2007).
Their findings further suggest the “integration of the individual
meanings of two seemingly unrelated concepts into a meaningful
metaphor expression” (Faust and Mashal, 2007, p. 860). When
faced with novel metaphor expressions, the right hemisphere sifted
through a large variety of related meanings and then chose the appropriate interpretation from this list (Faust and Mashal, 2007).
This relates to the indirect theory of metaphor comprehension
where the participants must reject the impulsive literal interpretation. Thus, the contextual significance may play a role in the understanding of the metaphor. Each word in the pair must be understood individually beyond its immediate definition.
In 2005, Sotillo, Carretie, Hinojosa, Tapia, Mercado, LopezMartin, and Albert (2005) also explored the brain’s hemispheres
and their roles in metaphor comprehension. ERPs were recorded on
thirty healthy right-handed individuals to investigate the bilateral
activation due to metaphors. These subjects were presented with visual representations of metaphorical and literal sentences, asked to
read the sentences out loud, and to judge whether the sentence was
metaphorical or not. An example of a visually presented metaphoric
sentence was “Green lung of city” (Sotillo et al., 2005, p. 5). The
specific area of activation for the metaphorical sentences was observed at the right middle/superior temporal gyrus (Sotillo et al.,
2005). The amplitude of the N400 portion of the ERP was used
as a marker for activation by metaphoric language stimulation. The
ERP amplitude in the right hemisphere was larger for the meta-
phorical sentences than for non-related words and semantic processing of literal linguistic stimuli (Sotillo et al., 2005). This activation is thought to be a reflection of a neural mechanism associated
with metaphor comprehension.
Some researchers have attempted to disprove the significance
of the right hemisphere in the understanding of metaphorical language. Shibata et al. (2007) performed fMRI while subjects read a
combination of sixty-three literal, metaphoric and anomalous sentences aloud in Japanese in the style “An A is a B” (Shibata et al.,
2007, p. 92). An example of a literal sentence was “The bus is a
vehicle.” Examples of the two other types were not provided. Participants read the sentences in their head and answered if they understood its meaning. When participants read metaphorical as opposed
to literal sentences, activation in the left medial frontal cortex, left
superior frontal cortex and left inferior frontal cortex (IFC) was detected. These specific regions may be necessary for processing semantic and pragmatic attributes unique to a metaphor. Thus, the
research team found a lack of right hemisphere involvement distinguished through metaphor processing.
Overall, the results are not yet indicative of whether metaphor
processing is direct, indirect or exclusively in the left hemisphere
because fMRI often possesses timing deficits (i.e. temporal resolution) (Shibata et al., 2007). Conducting a study in which both ERP
and fMRI are employed may alleviate this discrepancy. An ERP has
more precise temporal resolution, but fMRI has stronger localizing
ability. Also, it is unclear whether “metaphor processing begins with
a verification of semantic deviation and then semantic coherence is
established, or if these processes are executed in parallel” (Shibata
et al., 2007, p. 99). Overall the study may not contribute to the
support or rejection of the contextual metaphor theory because the
actual processing of the metaphor is not specifically and thoroughly
investigated.
Other researchers have also attempted to refute the selective
and/or exclusive role of the right hemisphere in metaphor processing. Lee & Dapretto (2006) asked participants to pair conventional
metaphors with their literal sentence pairs and underwent fMRI.
An example of this stimuli provided was the literal pair, “coldchilly” and the metaphor word pair, “cold-unfriendly” (Lee & Dapretto, 2006, p. 538). These sentences were paired for their similarity in word frequency, tense, connotation, and syntactic structure. It
was observed that the left prefrontal and temporo-parietal regions
were activated by the non-literal metaphoric sentences. Based on
their results, Lee & Dapretto (2006) argue that “prior reports of
greater RH [right hemisphere] involvement for metaphorical language might reflect the increased complexity of figurative language
rather than RH specialization for understanding metaphors” (p.
536). Thus the right hemisphere may simply be called upon for
very specific language processing.
Lee & Dapretto (2006) also support their argument with similar findings from past research. It has been shown that “a common
feature shared by these studies is that the subjects were presented
with incongruent or unexpected, semantic information that required a reinterpretation of the initial meaning as well as a retrieval
of additional semantic information” (Lee & Dapretto, 2006, p. 10).
Thus, the processing of metaphors may support the indirect theory and/or the contextual metaphor theory as the understanding of
the metaphor does not seem to be an immediate and direct process
within the neural circuitry. To date, the debate as to where metaphors are processed is ongoing.
The use of a unique set of subjects to explore the role of the
right hemisphere in metaphor processing has also been a popular
area of research in the field. These studies may also contribute to
the support or rejection of conceptual metaphor theory. Rinaldi et
al. (2004) employed fifty right-brain damaged patients and thirtyeight healthy controls to investigate the significance of the right side
in understanding pragmatics. For pragmatics, a connection between
a word and its context is necessary to understand the metaphor, as
the contextual metaphor theory implies. Visuo-verbal and verbal
tests were used to assess the understanding of metaphors and what
mental processes are lost or compromised in right-brain damage.
For the visuo-verbal stimuli, the subject was asked to match twenty
simple, common Italian metaphorical expressions with one of four
black and white drawings. The four drawings displayed represented
a correct metaphorical meaning, literal meaning, incorrect alternative metaphorical meaning or incorrect alternative literal meaning (Rinaldi et al., 2004). The subject was asked to choose which
among the set of drawings represented the correct meaning of the
metaphor. In the verbal test, the subjects had to match twenty other
metaphorical sentences created with the same criteria as the visuoverbal task. The subjects were then asked to match a card written
with a metaphorical expression with one of three cards displaying
the correct literal, control or metaphorical interpretation.
Rinaldi et al. (2004) concluded that the context of the metaphor was not sufficient for patients to derive the metaphor’s meaning. The findings have shown that patients with right-brain lesions
employed a literal interpretation with pictorial context and therefore were insensitive to the context provided in the metaphorical
phrases (Rinaldi et al., 2004). Patients had a lower frequency of
correct metaphorical choices. They could comprehend metaphors,
but often had trouble understanding their context. Furthermore,
the subjects performed more poorly on the visuo-verbal than on the
verbal tests. It is believed that the deficits suffered by right-hemisphere damaged patients may be due to a lack of “integration of information coming from two potentially intact processing channels”
(Rinaldi et al., 2004). These channels stem from different representational information systems within the brain and thus the context
may not be integrated or even necessary for the metaphor processing.
Rinaldi et al. (2004) recognize that the contextual metaphor
theory remains a popular topic of debate. However, based on the results, the team concludes that context is not the determining factor
in distinguishing between a literal and metaphorical phrase (Rinaldi
et al., 2004). They assert that in the verbal and visuo-verbal test, a
metaphorical-type context was always provided. They also indicate
that elements or words biased a subject towards the metaphorical
interpretation, rather than the literal (Rinaldi et al., 2004). Rinaldi
et al. (2004) conclude that if these right-brain damaged patients
were insensitive to context, they would have been equally weak
and/or equally literal on both tests, not just the visuo-verbal.
The use of metaphors in comprehending neurological function
in brain damaged patients has become a pertinent area of research.
Two of the most comprehensively studied disorders are Asperger
Syndrome (AS) and Alzheimer’s Disease (AD). AS is a high-functioning form of autism. Individuals afflicted with the disorder have
proficient linguistic abilities; however, they lack the interactive communicative skills to use their knowledge of language. They therefore
fall 2010 – eurj
27
possess a deficit in pragmatic language use or comprehension. AS
individuals have trouble with understanding non-literal linguistic phrases and interpreting a speaker’s intentions by their choice
of words (Martin and McDonald, 2004). For example, AS patients
are often “overly literal in their language comprehension and have
difficulty understanding narrative humor” (Martin & McDonald,
2004, p. 311). Thus, these mentally impaired patients are good test
subjects because they may or may not support whether the contextual understanding of a metaphor is necessary to fully comprehend
it.
Martin and McDonald (2004) explore the two predominant
theories that attempt to explain where deficits in pragmatic language occur in AS patients. They compare the theory of Weak Central Coherence (WCC) and the Social Inference/Theory of Mind
(TOM). WCC implies a lack of integrative ability in which one is
unable to use context to derive meaning. This would suggest a deficit in the contextual metaphor theory. For the WCC theory to hold
true, low level pragmatic language processing must occur across
several domains. These individuals concentrate on minute pieces of
information rather than a grander, coherent pattern of ideas. This
would be caused by malfunctioning of the integrative central system within the brain (Martin and McDonald, 2004) WCC is necessary for a range of tasks from the comprehension of simple visual
illusions to the understanding of pragmatics (Martin and McDonald, 2004).
In contrast, TOM indicates an ability to understand a speaker’s
intention and therefore to “form representations of other individuals’ mental states, and, furthermore, to use these representations
to understand, predict and judge others’ utterances and behavior” (Martin and McDonald, 2004, p. 312). Martin and McDonald (2004) highlight AS children’s deficit in TOM by referring to
Happe and Frith (2001). In Happe and Frith (2001), individuals
with autism understand metaphors strictly by their literal meaning, as the direct theory of metaphor comprehension implies. These
subjects are incapable of processing domain-specific pragmatic language at high levels. Martin & McDonald (2004) also believe that
this cognitive deficit occurs because of the lack of non-literal language comprehension.
In Martin and McDonald (2004), fourteen adults with AS
and twenty-four normal patients were evaluated. The study assessed
their ability to understand ironic sentences, Theory of Mind (TOM
and social inference capabilities), and WCC processing. It was
found that non-literal phrases posed a problem for pragmatic interpretation in AS individuals because the subjects would interpret
the ironic phrases as simply false statements (Martin & McDonald,
2004). Martin and McDonald (2004) conclude that both theories
hold true to a certain degree. Dennis, Lazenby, and Lockyer (2001),
referenced by Martin and McDonald (2004), argue in support of
TOM as AS subjects “found ambiguity easier than [understanding
a] metaphor, the difficulty interpreting pragmatic language must
come from the intentionality of the utterance and not simply from
the fact that it has multiple meanings” (p. 325). Also, in terms of
the WCC theory, AS subjects had trouble deciphering common
themes running through a series of statements, are unable to utilize
the contextual structure within a phrase to process its meaning, and
unfortunately may not achieve “local linguistic coherence” (Martin
and McDonald, 2004, p. 313).
In a similar paper focused on the language processing of autistic children, Dennis, Lazenby, and Lockyer (2001) hypothesized
that the main deficit lies in pragmatic inferences, even though these
28 eurj – fall 2010
children are capable of completing non-inferential tasks. Eight children with high-functioning autism and twenty four controls were
included. Four of the autistic children met Asperger disorder criteria and the remaining four were classified only with autistic disorder. Both autistic and Asperger patients had similar results on TOM
assessments. Although categorized with different developmental
disorders, these eight children were pooled together to garner a larger sample size for the study. They were evaluated for their ability to
match a metaphor to its shared structural meaning in a metaphor
task. The subjects were given a figurative phrase such as, “‘I have
butterflies in my stomach’” with a description of the context such
as “‘This is what a girl said about her first day in school’” (Dennis et
al., 2001, p. 50). They were then asked to match the metaphorical
phrase to its figurative meaning from a choice of four visual representations. Three were incorrect, including: an opposite interpretation, a literal interpretation, and a related literal interpretation. The
metaphors used were predominantly structural (conventional), orientational, and ontological. Orientational metaphors are spatially
related concepts and ontological metaphors represent concrete concepts (object, substance, person) (Lakoff and Johnson, 1980).
Overall, the Dennis et al. (2001) hypothesis was supported,
even though some “flexible linguistic competence” (p. 51) was observed. The control group performed three times as well with the
metaphor tasks. Yet, the AS patients acquired many of the language
skills that others their age were only beginning to master such as
defining words and listing various meanings for ambiguous words.
Unfortunately, they still could neither adequately comprehend the
metaphor nor decipher the speaker’s thought process. They understood the variety of meanings a word may possess, but could not
choose which one the speaker intended to use. Dennis et al. (2001)
emphasized the importance of these verbal skills as they are at the
core of communication in society. These children may lack the
ability to understand an individual’s mental states, thereby failing
to comprehend the beliefs or intentions of others (Dennis et al.,
2001). This may impair their social cognitive skills, hindering the
awareness of the mind and thought.
With AD, patients undergo gross neuronal and brain mass
losses and thus incur several diverse deficits with cognitive functions. Several of the most common symptoms include: aphasia,
loss of memory, global cognitive deficits, behavioral inhibition, and
impairments in spontaneous speech. Patients with AD are able to
understand phonemic structures, but display deficits in communication and semantics (Amanzio et al., 2008). Phonemic structures
refer to the ability to understand the individual sounds in spoken word. Amanzio et al. (2008) hypothesized that the prefrontal
cortex, an area deeply impaired in AD patients, may play an integral role in novel metaphor comprehension. The prefrontal cortex is significant for many neuronal processes which may affect the
comprehension of novel metaphors. Twenty control patients and
twenty patients with probable AD were tested for their understanding of non-literal language. Twenty nominal metaphors were used
and subjects were asked to provide an interpretation of the phrases’ meanings. An example provided was “That student is a peak”
(Amanzio et al., 2008, p. 4). Poorer performance with novel metaphors was observed in patients with probable AD (These patients
were tested using the Behavioral Assessment of the Dysexecutive
Syndrome, BADS).
Amanzio et al. (2008) believe that the deficit in novel meta-
phor comprehension results from the deterioration of the prefrontal cortex. Some of their deficits include executive function, verbal
reasoning, problem-solving, and memory. It is believed that the
prefrontal cortex influences a “functional interdependence between
executive function and Theory of Mind, and their relationship with
the prefrontal cortex” (Amanzio et al., 2008, p. 3). This visual-spatial assessment using the BADS key-search test provided evidence
of a correlation between weak novel metaphor comprehension and
impaired executive function in the frontal brain regions.
The frontal areas of the brain also facilitate working memory.
Impairments may stem from the inability to integrate metaphors
into long term memory stores. This requires the incorporation of
language use and ideas into one’s general knowledge (Amanzio et
al., 2008). Amanzio et al. (2008) believe that “all forms of immediate thought, from reasoning to sentence comprehension, entail
the manipulation and temporary storage of information and for
that reason a central role is attributed to working memory” (p. 8).
Therefore, in order to quickly and efficiently comprehend unconventional metaphors, this neural network must be robust. Not only
had Amanzio et al. (2008) pinpointed an area of the brain necessary
for novel metaphor comprehension, but they also recognized what
functions of the frontal cortex are compromised during this process.
In another significant study by Papagno (2001), thirty-nine
patients with probable AD were used to analyze the neural mechanisms impaired in metaphor comprehension in early dementia.
The Milan Overall Dementia Assessment (MODA) was utilized to
determine the degree of neurological function and patients with a
mild to moderate amount of illness were selected. (Papagno, 2001).
Metaphors and idioms were employed to investigate the deficits in
figurative language processing by AD patients. An example of an
idiom used is, “‘to be at the green’” which translated from Italian
roughly implies “‘to be completely out of money’” (Papagno, 2001,
p. 1456). Subjects were asked to translate these phrases into their
most literal interpretation. Papagno (2001, p. 1453) mentions previous research by Moscovitch and Umilta (1990) in which they argue that even with non-focal brain damage, as seen in AD patients,
the cognitive functions that stay intact may be “informationally encapsulated”. Thus even with intellectual deficits, certain cognitive
abilities may not be affected by the loss of general knowledge, possibly including context.
Overall, the ability to comprehend metaphors was not impaired in early or more developed cases of Alzheimer’s as only
four of the thirty-nine subjects were unable to comprehend figurative language (Papagno, 2001). Figurative language was actually
the least impaired of all the linguistic tools which Papagno (2001)
suggest is because there may be a limited impairment to areas in
the right hemisphere attributed to metaphor and idiom comprehension. Also, rather than a specific brain region allowing figurative language understanding, Papagno (2001) suggests that there is
a “distributed neural network” (p. 1462) for figurative language as
there is for literal language.
As researchers explore the role of the conceptual metaphor
theory within the brain, subcategories emerge that attempt to distinguish the areas of the brain activated by specific metaphor subgroups. Certain studies have investigated the neuronal implications of the theory which suggest that metaphorical understanding
is created by neuronal mapping. These mappings are grouped by
areas of the brain that process specific physical experiences. Chen,
Widick and Chaterjeem (2008) examined the neurological processing of predicate metaphors. More specifically, the team explored the
neuronal organization of predicate motion metaphors. In contrast
to noun metaphors, predicate metaphors employ verbs as the concepts of comparison, such as “The man fell under his spell” (Chen
et al., 2008, p. 195). The interest in this subcategory of metaphors
stems from the belief that not all metaphors are processed alike. It
is argued that the level of abstraction of language might determine
where in the brain a category of metaphors may be processed (Chen
et al., 2008).
In this study by Chen et al. (2008) fourteen participants underwent fMRI while performing a task where they decided if the
sentence presented was plausible to use in everyday speech. The
results contrasted the brain activation of the predicate metaphors
versus the literal motion sentences. Greater activation in the left
hemisphere in general was identified (Chen et al., 2008). More specifically, there were significant activations of the left posterior middle temporal gyrus, left angular gyrus and left inferior frontal gyrus.
In terms of motion metaphors, there is a posterior-anterior axis of
increasing abstract processing through the lateral temporal cortex.
The more literal, concrete motion language processing occurs in the
posterior inferior temporal gyrus. The more abstract language activates the posterior middle temporal gyrus and even the superior
temporal gyrus (Chen et al., 2008). These results can be interpreted
in light of sensory-functional theory, proposing that “non-living
things [concepts] are distinguished from one another primarily in
terms of their functional properties” (Martin & Caramazza, 2003).
In effect, the concepts acquired through experiences are ingrained
within or near the sensory-motor areas by their relevance to physical experiences. Chen et al. (2008) proposed that these motion
metaphors include spatial concepts with both sensory-motor and
abstract features. The research team believes that, “In predicate motion metaphors, the sensory-motor attributes are shed, and the remaining core abstract conceptual features are highlighted to establish the meaning of the metaphor” (Chen et al., 2008, p. 7).
Lacey, Anderson, Stilla and Sathian (2008) corrected certain
weaknesses inherent in the Chen et al. (2008) methodology. Firstly,
Chen et al. (2008) investigated the conceptual metaphor theory,
but did not run a localizer task to identify motion-selective areas in
their subjects. They simply looked at how the degree of abstraction
of a motion metaphor causes activation of different anterior/posterior regions. Furthermore, several factors of the metaphors used
in the Chen et al. (2008) paradigm were assessed including: word
length, frequency, concreteness, imageability, and figurativeness. In
Chen et al. (2008), the frequency varied too greatly between the
predicate metaphors, literal motion sentences and non-motive sentences. The study therefore lacked an important control variable.
Lacey et al. (2008) used fMRI during a texture perception task
to localize visual, haptic, and bisensory texture-selective cortical areas in their participants. In a separate fMRI session, participants listened to sentences containing a texture metaphor and control sentences that contained the literal meaning of the metaphors. In the
task, participants pressed a button when each sentence was understood. The results showed that during the presentation of textural
metaphors, the somatosensory cortex was activated in the parietal
operculum, bilateral OP1 and left OP3, an area previously found
to be texture-selective in touch (Stilla and Sathian, 2008). However, neither the visual nor bisensory texture-selective areas were
significantly activated during the texture metaphor task. By confining metaphors only to the domain of texture, Lacey et al. were able
fall 2010 – eurj
29
to show sensory-specific activity in the somatosensory cortex. These
findings provide support for the idea that cognition is grounded in
perception and that the understanding of metaphors stems from
perception.
Conclusion
There have been several theories put forward and many unique
subject groups used to analyze what is necessary to comprehend
a metaphor. The conceptual metaphor theory emphasizes the importance of human experience and its ability to shape our understanding of language. It relies on the basic concept that in order
to understand a metaphor one must call upon his or her physical
perception and experiences. As discussed earlier, many of the rightbrain damaged patients lose their ability to comprehend the context
of metaphorical phrases as implied by the WCC theory and contextual theory of metaphor processing. Although in some cases the
theory mentioned above is well supported, it remains inconclusive
whether metaphor comprehension may be attributed mainly to the
understanding of a word’s meaning and context and what that may
imply.
Furthermore, Lacey et al. (2008) reinforce the use of physical
perception by exploring sensory-specific metaphors in neuroimaging. The research team highlighted that the use of textural attributes
allows for the activation of the texture-selective somatosensory cortex. This most likely occurs because texture is salient to touch. A
specific somatosensory area of the cortex is recruited to assess the
contextual relevance of the concepts within the metaphor. Therefore, the brain’s inherent categorization through sensory mappings
promotes this specific sensory activation.
There are several avenues to explore in order to further our
understanding of metaphor processing. For example, future work
may expand upon Lacey et al. studies by exploring the activation
of different areas of the somatosensory cortex by various sensoryselective subjects. Further investigation into the ability of left-hemisphere brain damaged patients to understand metaphors should be
pursued. Overall, a vast amount of research remains to be done on
metaphor processing within the brain. This research is crucial for
its contribution to the understanding of neural mechanisms behind
language processing. Moreover, these studies may contribute to the
expanding library of knowledge dealing with how information is
integrated within the brain. Through the exploration of metaphor
processing, we are moving along a path to a more extensive understanding of the neuronal mechanisms and regions of the brain attributed to language processing.
References
Amanzio, M., Geminiani, G., Leotta, D., & Cappa, S. (2008). Metaphor comprehension in Alzheimer’s disease: Novelty Matters, Brain and Language, 107,
1-10.
Bottini, G., Corcoran, R., Sterzi, R., Paulesu, E., Schenone, P., Scarpa, P., Frackowiak, R.S., & Frith, C.D. (1994). The role of the right hemisphere in the interpretation of figurative aspects of language. A positron emission tomography
activation study. Brain, 117, 1241-1253.
Chen, E., Widick, P., & Chatterjee, A. (2008). Functional-anatomical organization
of predicate metaphor processing. Brain and Language, Article in Press.
Dennis, M., Lazenby, A.L., & Lockyer, L. (2001). Inferential language in HighFunction Children with Autism. Journal of Autism and Developmental Disorders, 31: 47-54.
Fass, D. (1986). Collative Semantics. Association for Computational Linguistics, 1,
341-343.
30 eurj – fall 2010
Faust, M., & Mashal, N. (2007). The role of the right cerebral hemisphere in processing novel metaphoric expressions taken from poetry: A divided visual field
study. Neuropsychologia, 45, 860-870.
Feldman, J., Lakoff, G., & Howell, S.R. (2000). Metaphor, Cognitive Models, and
Language. McMaster University, 1-12.
Giora, R. (2004). On the graded salience hypothesis. Intercultural Pragmatics, 1,
93-103.
Howe, J. (2008). Argument is argument: An essay on conceptual metaphor and verbal dispute. Metaphor and Symbol, 23, 1-23.
Keysar, B., & Bly, B. M. (1999). Swimming against the current: Do idioms reflect
conceptual structure? Journal of Pragmatics, 31, 1559-1578.
Lacey, S., Anderson, A., Stilla, R., & Sathian, K. (2008). Metaphorically feeling: somatosensory texture-selective cortex is active during comprehension of textural
metaphors (Society for Neuroscience Abstract).
Lakoff, G. & Johnson, M. (1980). Metaphors We Live By. Chicago: The University
of Chicago Press.
Lee, S.S., & Dapretto, M. (2005). Metaphorical vs. literal word meanings: fMRI
evidence against a selective role of the right hemisphere. Neuroimage, 29, 536544.
Martin, A., & Caramazza, A. (2003). The organization of conceptual knowledge in
the brain. Cognitive Neuropsychology, 20, 195-502.
Martin, I., & McDonald, S. (2004). An Exploration of causes of non-literal language problems in individuals with asperger syndrome. Journal of Autism and
Developmental Disorders, 34, 311-328.
Merriam-Webster’s Collegiate Dictionary. 11th ed. 2003.
Murphy, G.L. (1997). Reasons to doubt the present evidence for metaphoric representation. Cognition, 62, 99-108.
Papagno, C. (2001). Comprehension of metaphors and idioms in patients with Alzheimer’s disease. Brain, 124, 1450-1460.
Rinaldi, M.C., Marangolo, P., & Baldassarri, F. (2004). Metaphor comprehension
in right brain-damaged patients with visuo-verbal material: A dissociation
re(considered). Cortex, 40, 479-490.
Shibata, M., Abe, J., Terao, A., & Miyamoto, T. (2007). Neural mechanisms involved in the comprehension of metaphoric and literal sentences: An fMRI
study. Brain research, 1166, 92-102.
Sotillo, M., Carretie, L., Hinojosa, J.A., Tapia, M., Mercado, F., Lopez-Martin, S.,
& Albert, J. (2005). Neural activity associated with metaphor comprehension:
spatial analysis. Neuroscience Letters, 373, 5-9.
Stilla, R., & Sathian, K. (2008). Selective visuo-haptic processing of shape and texture. Human Brain Mapping, 29, 1123-1138.
The Freshman Fifteen:
A Case Study at Emory University
Josh Katz
‘12 C
key terms
Freshman Fifteen - The often-reported, yet unsubstantiated claim that freshmen typically gain fifteen pounds during their first year of college. The purported causes of this
weight gain are increased alcohol intake and the consumption of high-fat and carbohydrate-rich food in all-you-can-eat cafeterias.
BMI - Body Mass Index, a statistical measure which compares a person’s weight and
height.
Jessie Preslar
‘12 C
Jessie Preslar is originally
from Myrtle Beach, SC.
She is currently a junior at
Emory majoring in NBB
and minoring in Global
Health, Culture, and Society. She plans on going
in to some aspect of public
health after her undergraduate studies.
Josh Katz is a junior from
Los Angeles, California. He
intends to graduate with a
Bachelor of Business Administration with a concentration in Accounting after
studying the next two years
with the Goizueta Business
School.
Rahul Varman
Diana Woodall
Rahul Varman is a junior
at Emory University double majoring in NBB and
Chemistry. Previous research experience includes
research on transdermal
drug delivery. Rahul hopes
to continue research regarding the brain and go to
medical school through an
MD/PhD program.
Diana Woodall is a junior
from Cary, NC majoring in
Biology and Sociology. After her undergraduate studies, she hopes to pursue an
M.D. and eventually specialize in emergency medicine.
‘12 C
‘12 C
Introduction
In conducting our study, we sought to explore the validity behind one of the most prominent myths associated with college: the
Freshman Fifteen. For many incoming freshmen, the prospect of
entering a new, foreign environment, devoid of any parent oversight, can be both difficult and stressful. Regardless of the truth of
the myth, the Freshman Fifteen can often feel like a looming possibility. Previous studies conducted over the past twenty years found
that weight gain during the first semester of college is a real phenomenon, although subjects gained, on average, less than fifteen
pounds. One such study found that college freshman gain an average of 2kg (4.4lb) during the first three months, citing ‘all-you-caneat’ dining halls, snacking, and high-fat junk food as the primary
contributors (Hodge, 1993). A similar study at Dartmouth College
found that freshman gain an average of 3.5-4 pounds, an amount
considerably greater than that observed in the general population,
yet far short of the infamous fifteen (Holm-Denoma, 2008). Such
studies served as a model for our investigation of college weight gain
and a reference for the many factors that contribute to the freshman
fifteen.
The objective of this study was to answer the central question:
“Is the freshman fifteen a real phenomenon?” The study attempts
to determine which lifestyle factors affect the “freshmen fifteen,”
as well as the impact of race and gender. It was hypothesized that
freshmen at Emory gain on average five pounds in their first semester, contrary to the fabled “freshmen fifteen.” The most significant
factors affecting weight gain were predicted to be eating frequency
and exercise frequency, although eating schedules and stress from
the new environment may also play a minor role. Weight gain was
thought to be independent of race or gender.
Participants
Eighty college freshmen at Emory participated in the study.
The study included twenty students each from the dorms Complex,
Evans, Few, and Harris. Subjects included a mix of males and females, various ethnicities, and people from different floors. All participants were selected at random.
Methods
Participants were asked to report their weight prior to starting
college, or if unknown, the weight listed on their most recent driver’s license. Participants were then weighed at the time they completed the survey, and the difference was calculated. If students were
uncomfortable disclosing their weight, they had the option to report only their change in weight from before college to the present.
All participants were weighed in clothes with their shoes off and
without jackets or heavy items in their pocket. Participants tended
to dress in a similar fashion (jeans and a shirt); thus, it was unlikely
that there were large differences in the weight of clothing between
subjects. Participants were also asked to complete a survey regarding their lifestyle, eating, and exercise habits. The questionnaire
was somewhat broad in order to consider many aspects regarding
weight gain. This survey asked students to describe and compare
their habits in high school and college. All data were entered into
an excel spreadsheet in order to perform calculations including average weight gain, BMI, average change in BMI, and Pearson correlation. Graphs were constructed to visualize linear trends and statistical methods, such as correlation between a variable and weight
gain, were used to augment the data analysis. An analysis of the
32 eurj – fall 2010
yes/no questions was also performed by quantifying the percentage
of respondents who gained, maintained, and lost weight based on
their response to a particular yes/no question.
Survey
The questionnaire (Appendix 1) obtained detailed information
about students’ lifestyle related to their eating, sleeping and exercising habits during high school and the first semester of college. Responses included a mix of qualitative, yes/no, numerical scale, and
free response answers. The results from the questionnaire were kept
anonymous and confidential and were used in all statistical analyses. Participants agreed to sign an informed consent (Appendix 2)
acknowledging their participation in the study.
Results
The overall average weight change for all of the participants was
a gain of 2.85 lbs. The amount of weight change ranged from -15.5
lbs to +15 lbs. Men gained an average of 2.33 lbs, while the average weight of women increased by 3.45 lbs. Asians gained 1.99 lbs
on average, whites 3.38 pounds, and African Americans 3.36 lbs.
Of all participants, 67.5% gained weight since coming to college;
of those who gained weight, the average weight gain was 5.9 lbs.
13.8% of the freshmen surveyed were the same weight at the time
of the survey as before college. Since coming to college, 18.8% of
participants lost weight; the average weight loss of this group was
6.0 lbs.
Participants were also categorized by weight status according
to their BMI, a statistical measurement which compares a person’s
weight and height. It is calculated by taking an individual’s body
weight in kilograms and dividing by the square of their height in
meters. A total of 2 (22%) of the 9 participants originally classified
as underweight (BMI<18.5) in August were reclassified to normal
in November (BMI≥25 and 30, respectively). In contrast, all 60
(100%) of participants originally classified as normal remained in
the normal weight category. Of the participants classified as overweight in August, 1 (11%) lost sufficient weight to be reclassified
as normal in November. The average BMI change over all surveyed
was an increase of 0.42. The average change in weight of those classified as underweight according to BMI was a gain of 3.8 lbs. Of
participants in the normal range of BMI, there was an average gain
of 3.7 lbs. The participants in the overweight category according to
BMI on average lost 3.8 lbs.
The data were analyzed using a Pearson Correlation, testing
the strength of the relationship between two variables. Because a
combination of many factors contribute to overall weight gain, a
strong correlation was defined to be r >.1414 (R2 > .02), a moderate correlation .1< r < .1414 (01< R2 < .02), and a poor correlation r <.1 (R2 < .01). According to these standards, change in
weeknight sleep, change in happiness, and number of meals at the
DUC showed a strong correlation to weight change, while change
in stress, change in number of meals, and snack amount exhibited a
moderate correlation. The strongest correlation was between weight
change and change in hours of sleep: people getting less sleep in
college in general gain more weight. Change in relative snacking,
on the other hand, is very poorly correlated with weight change.
Three variables indicate a direct relationship with weight gain: individuals who eat more meals, snack often, or eat more meals at the
DUC tend to show increased weight gain. Four variables show an
inverse relationship with weight gain: those who are more stressed,
sleep less, are more happy, and snack less than in high school tend
fall 2010 – eurj
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Figure 1 - Change in Stress vs. Change in Weight
Figure 2 - Change in Number of Meals vs. Change in Weight
Figure 7 - Number of Meals at the DUC vs. Change in Weight
Figure 8 - Breakfast Habits vs. Change in Weight
Figure 3 - Change in Weeknight Sleep vs. Change in Weight
Figure 4 - Change in Relative Happiness vs. Change in Weight
Figure 9 - Consistent Eating Times vs. Change in Weight
Figure 10 - Dieting vs. Change in Weight
Figure 5 - Change in Number of Snacks vs. Change in Weight
Figure 6 - Number of Snacks vs. Change in Weight
Figure 11 - Health Consciousness vs. Change in Weight
34 eurj – fall 2010
fall 2010 – eurj
35
to gain more weight. Several variables had no correlation to weight
gain including residence hall, hours of exercise per week, and number of alcoholic beverages consumed per week.
Although the yes/no questions were not analyzed using statistical methods, it is still possible to draw some conclusions from the
data by looking at the percentage of people in each category who
lost, maintained, and gained weight. When comparing individuals
who lost weight to individuals who gained weight, it appears that
eating breakfast has no correlation to weight change. However,
when comparing those who gained weight to those who did not
gain weight (i.e. grouping participants who lost and maintained
their weight), it becomes evident that breakfast does have an effect
on weight change: those who do not eat breakfast are 7.4% more
likely to gain weight. Consistent eating times appeared to have no
effect on weight change; those who ate at scheduled times gained
weight 71.5% of the time vs. 69.8% for those who did not have a
schedule. Intentionally dieting had a significant impact on weight
change: individuals who do not diet are 11.2% more likely to gain
weight. Health consciousness also showed a strong positive correlation with weight gain: participants who described themselves as
health conscious were 14.4% more likely to gain weight.
Discussion and Conclusion
This study examines the weight change of first-year college
students and explores demographic, nutritional, and lifestyle factors related to the trend. Consistent with current research, the
results of our study indicate that freshman in college gain weight
during their first semester, although the average weight increase is
less than fifteen pounds. Our finding of a 2.85 lb average gain is
slightly less than the results of other studies, which reported average weight gains of 4.4 lbs, 3.5-4.0 lbs, 5.0 lbs, and 5.0 lbs (Hodge,
1993, Holm-Denoma, 2008, Anderson, 2003, Brown 2008). The
weight gain indicated by our current study was substantial enough
to support the findings of Megel et al. (1994) and Levitsky et al.
(2004), such that the average weight increase upon entering college is significant (i.e., well above national averages for weight gain).
Our results mirror those reported by Anderson et al. (2003) in that
participants appeared to gain weight early in the year, usually by
November or December. Findings differed in the specific factors attributed to weight gain; while we found that all-you-can-eat dining, decreased sleep, and increased happiness contributed to weight
gain, other studies have cited troublesome relationships with parents (Holm-Denoma, 2008), reduction in physical activity (Jung,
2008), snacking and eating junk food (Hodge, 1993), and low selfesteem (Levitsky, 2004). Only one study offered all-you-can-eat
dining halls as an explanation for weight gain (Hodge, 1993), while
no studies reported the effect of sleep or happiness. Such a wide
variance may be attributed to the particular nature of the study in
how questions were presented, the institution at which the study
was conducted, the demographics of the students surveyed, the year
in which the study was conducted, or the focus of the researchers.
Further studies should be conducted to confirm the impact of certain factors on freshman weight gain.
Findings also confirmed our hypothesis that freshman gain less
than the fabled fifteen pounds during their first semester. However, while we predicted a mean weight gain of five pounds, the actual average was fairly less at 2.85 lbs. Although weight gain was
thought to be independent of race or gender, results indicated that
females gain on average 48% (1.12 lb) more than males, and Asians
gain 41% less than African Americans and whites. Such significant
36 eurj – fall 2010
differences could not be explained by the data, and it is possible the
variations are overestimated due to the small sample size of participants. The location of an individual’s dorm appeared to have no effect on weight change, as students in each of the four dorms gained
close to the overall average.
Analysis revealed a weaker than expected correlation between
change in eating frequency (measured by the number of meals per
day) and weight gain, with r=0.141, and between change in stress
and weight gain, with r=0.110. The measurement of eating frequency may have weakened the correlation in that people who eat
fewer meals may have many more snacks. In future analysis, these
two factors should be studied together to encompass eating frequency. The reason for only a moderate correlation between stress
and weight gain may be on the individual level; while stress causes
some individuals to eat more, it can also have the opposite effect.
Thus, the effect of stress on weight fluctuation may be understated.
Contrary to predictions, exercise frequency indicated even less correlation with weight gain and was statistically insignificant. Inconsistent eating schedules, which were expected to play a minor role
in freshman weight gain, showed no correlation.
The factors that did impact weight fluctuation were change
in hours of weeknight sleep, change in happiness, and number of
meals eaten at the DUC. As people sleep less, they tend to gain
more weight, possibly because they have more time to eat. This
finding is consistent with recent studies that have linked sleep deprivation to weight gain, reporting that hormone levels can be affected after as few as two nights of poor sleep, triggering alterations
in the brain’s chemistry that increase appetite. Change in weeknight
sleep was the greatest predictor of weight gain, although it is possible that sleep deprivation is tied into the college lifestyle and is
therefore less of a factor in weight gain than our study suggests.
Change in happiness is also correlated with weight fluctuation:
individuals who are happier than in high school have gained more
weight than others. A possible explanation for this trend is that individuals who are happy in college tend to have less stress and more
time to eat. They may also have many friends whom they can go to
the DUC with. Number of meals eaten at the DUC was the second greatest predictor of weight gain in that students who eat at
the DUC more often are more likely to gain weight. This may be
attributed to the all-you-can-eat style of the cafeteria as well as the
significant number of unhealthy options.
There are several limitations to this study. Because the initial
weight was self-reported, it is possible that participants may have
under or overestimated their weight. Women in particular are more
likely to underestimate their weight, thus it is possible that the average change in weight for women was inflated. Inaccuracy in reporting weight may have also skewed the BMI changes calculated
in this study. Heavier people may underestimate their weight, and
height tends to be over inflated; thus, the weight and BMI changes
we calculated may be low estimates. Also, because three different
scales were used in the study, and many other scales were used by
individuals to report their initial weight, there may be unintentional inaccuracies in the calculated differences. Disparities between
scales could introduce a significant amount of error into the data.
It is also a limitation that body composition was not measured.
This makes it unclear as to whether participants may have gained
weight due to an increase in muscle (which may be a positive
weight change indication) or unwanted gain of fat (which maybe
a negative weight change indication). Athletes were not excluded
from the study; thus, it is possible that a number of participants
who gained weight increased their muscle mass rather than adding
fat. Future studies should seek to measure the source of weight fluctuation using body composition measurements.
Several students refused to participate in the study, particularly
women who tended to be heavier than average. This may have led
to an underestimate in the average weight gain calculated in our
study. These students may have also had different nutrition and
physical activity behaviors that affected weight change, yet were not
included in the study. Thus, our demographics were not representative of the entire freshman student population at a university, a factor that may have significantly impacted the results.
The use of data from a single institution where most respondents were middle-upper class limits the ability to generalize beyond private universities with predominantly homogenous student
populations. Further research is needed to confirm these findings in
other populations and to explore whether similar factors are correlated with weight change over the freshman year. It would be useful
for future researchers to compare weight gain in private universities to that in public universities and community colleges and to
determine the effects of different factors in different environments.
Finally, we did not compare the weight fluctuation of college freshmen with those of another group of similarly aged individuals not
attending university. Such a comparison could reveal the effect of
university life on weight change vs. weight gain due to age alone.
Furthermore, our study did not delve into the social conditions
shaping the experience of college freshman that might influence
weight gain. Social pressures that influence where and how students
eat and exercise should be examined by future researchers in order
to determine the social and emotional basis of freshman weight
gain. Peer pressure to drink alcohol or to conform to a certain body
image may also contribute or help avoid weight gain.
Although our findings indicate that college freshman gain
less than the legendary fifteen pounds, the significant increase in
weight during the first semester suggest opportunities for health
awareness during the transition from high school to college life.
Future researchers should concentrate on the mechanisms of freshman weight gain and on interventions to avoid unhealthy weight
increase. In future studies, men and women could be separated to
analyze the factors contributing to weight gain for each gender.
Studies could be conducted as to the impact of all-you-can-eat dining halls by closing these facilities on a campus and instead opening smaller restaurants that require students to purchase their meals.
The impact of stress could be further analyzed by asking students
whether stress causes them to eat more or avoid eating. Weeknight
and weekend sleep could be further explored by selecting participants who go to bed at a variety of times, as well as testing whether
hours of sleep is linked to stress. Future researchers should keep
in mind the average lifestyle of a college student, particularly the
lack of sleep, irregular eating habits, and stress levels in determining
how the combination of these habits may contribute to the freshman weight gain. A better understanding of these factors as they
relate to weight gain is crucial for preventing the “freshman fifteen”
and would mark the first step in helping lessen the overall trend of
weight gain in our society.
15: Tracking Physical Activity and Dietary Patterns in 1st-Year University
Women. Journal of American College Health, 56(5), 523-30.
Brown, C. (2008). The information trail of the ‘Freshman 15’—a systematic review
of a health myth within the research and popular culture. Health Information
& Libraries Journal, 25(1), 1-12.
Economos, C. D., Hildebrandt, M. L., Hyatt, R. R. (2002). College Freshman
Stress and Weight Change: Differences by Gender. American Journal of Health
Behavior, 32(1), 16-25.
Graham, M. A., & Jones, A. L. (2002). Freshman 15: Valid theory or harmful myth?
Journal of American College Health , 50, 171-173.
Hodge, C. N., Jackson, L. A., & Sullivan, L. A. (1993). The “Freshman 15:” Facts
and Fantasies About Weight Gain in College Women. Psychology of Women
Quarterly (17), 119-126.
Hoffman, D. J., Policastro, P., Quick, V., Soo-Kyung, L. (2006). Changes in Body
Weight and Fat Mass of Men and Women in the First Year of College: A Study
of the Freshman 15. Journal of American College Health, 55(1), 41-45.
Holm-Denoma, J. M., Joiner Jr., T. E., Vohs, K. D., Heatherton, T. F. (2008). Freshman fifteen (the “Freshman Five” actually): Predictors and possible explainations. Health Psychology, 27(1), S3-S9.
Huang, Y., Song, W., Schemmel, R., &, S. (1994). What do college students eat?
Food selection and meal pattern. Nutrition Research, 14, 1143.
Levitsky, D., Halbmaier, C., & Mrdjenovic, G. (2004). The freshman weight gain: a
model for the study of the epidemic of obesity. International Journal of Obesity
, 28, 1435–1442.
Mihalopoulos, N. L., Aulinger P., & Klein J. D. (2008). The Freshman 15: Is it real?.
Journal of American College Health, 56(5), 531-533.
Von Ah Hoerr, D., & al, e. (2004). Predictors of health behaviours in college students. Journal of Advanced Nursing, 48 (5), 463-474.
emory
students,
Apply to ...
eurj
Works Cited
Anderson, D. A., Shapiro, J. R., Lundgren, J. D. (2003). The freshman year of college as a critical period for weight gain: An initial evaluation. Eating Behaviors,
4(4), 363-367.
Bray, S. R., Ginis, K. A., Jung, M. E. (2008). Behavior Change and the Freshman
fall 2010 – eurj
37
Appendix 1
Survey
Background
Age:
Height:
Now
Sex:
Ethnicity:
Dorm/Floor:
August, 2008
Weight (lb):
OR
Change in weight since August 2008 (use + to indicate weight gain and – to indicate weight loss):
Lifestyle
Hours of sleep on an average weeknight?
Hours of sleep per night on an average weekend?
Number of alcoholic beverages consumed in a given
week?
Do you smoke? If so, how many cigarettes per day?
Average level of stress on a scale of 1-5, 1 indicating no
stress and 5 indicating great stress?
Emotional state on a scale of 1-5, 1 being happy and 5
being sad
Diet and Eating Habits
How many meals do you eat per day?
At the DUC?
At another campus dining facility?
Do you eat breakfast?
How many servings of fruits/veggies per day?
How many snacks do you eat per day?
What kind of snacks?
What do you typically drink?
Do you eat at consistent times every day?
Do you keep food in your room? If so, what kind of
food?
Do you purposely engage in dieting activities?
Exercise
How many hours do you exercise in a given
week?
What type of exercise?
How much time a day would you estimate you
spend walking?
Stairs or elevator?
College
College
College
High school
High school
High school
Free Response
To what extent do you consider yourself to be health-conscious? Has this changed since coming to
college?
38 eurj – fall 2010
Appendix 2
Informed Consent
Title: Freshman 15 in first year students at Emory
Principal Investigator: Diana Woodall, Rahul Varman, Joshua Katz, Jessica Preslar
Sponsor: ORDER class
Introduction and Purpose: You are invited to take part in a research study. The purpose of the study is to research the
validity behind the common idea of the Freshman 15 – gaining 15 pounds in the first year of college. Although many
students think and worry about this, the point of this experiment is to investigate if there is any support for this
conception and determine if there are any trends in weight change. This study is being conducted for the ORDER class,
a freshmen seminar at Emory focused on research.
Procedures: You are being asked to fill out this survey to provide information on weight, eating habits, exercise, and
other lifestyle habits. This data will then be analyzed to see if freshmen do gain or lose a significant amount of weight and
to look for any other trends that may emerge. There will be no further participation beyond the initial survey.
Risks, Discomforts, and Inconveniences: The only known risk to participation is possible breach in confidentiality or
possible emotional discomfort at disclosing sensitive personal information. However, all possible precautions will be
taken to minimize these risks. You may also choose to stop participating at any point if you become emotionally
unsettled.
Benefits: This survey will not benefit you in any immediate way. The information gathered may be used to suggest
behaviors or lifestyles that are associated with less weight gain.
Confidentiality: Your name will not be included anywhere in this experiment, associated with your survey or in any
other form. The surveys that are collected will be kept by the researchers or the teachers of the ORDER class.
Contact Persons:
Jessica Preslar, researcher:
Email: jpresla@emory.edu
Emory IRB, for problems, questions, complaints, concerns or questions about your rights as a research participant:
Call toll-free at 1-800-503-9797 or (404) 712-0720; email irb@emory.edu; or write to the office at 1599 Clifton Road,
Atlanta GA 30322.
It’s Your Choice: You are free to choose whether or not you want to take part in this study. You can change your mind
and stop at any time without penalty. This decision will not adversely affect your relationship with the researchers or
Emory. It will not affect any benefits you may receive outside of the research. It’s your choice.
Withdrawal: The lead researcher and/or sponsor may withdraw you from the study if they decide that it is in your best
interest.
If you are willing to volunteer for this research, please sign below. You do not give up any rights by signing this form.
You may keep a copy for your records.”
______________________________________________ ___________ __________
Subject's name /Signature
Date
Time
________________________________ ___________ __________
Legally Authorized Representative
Date
Time
(if required)
________________________________ ___________ __________
Person Obtaining Consent
Date
Time
fall 2010 – eurj
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