Unit 2 Research Methods
Goals of Psychological Research
•
Description of social behavior
– Are people who grow up in warm climates different
from those in cold climates?
• Establish a relationship between cause &
effect
– Does heat cause higher amounts of aggression?
• Develop theories about why people behave
the way that they do
– We dislike Duke students to feel better about
ourselves
• Application
– Creating effective therapeutic treatments, more
successful negotiation tactics, and greater
understanding amongst groups of people
Scientific Method
Create testable
operational
definitions
Be curious.
Question your
world.
Collect data using
DESCRIPTIVE
Research
Conduct more
research
Naturalistic
Observation
Survey
Case
Study
Form a
Hypothesis
Relationship?
CORRELATION
Causation?
EXPERIMENT
Doesn’t support
the hypothesis
Continue to
retest
Use this to
predict and
explain the world
Supports the
hypothesis
Create a Theory
Unit 2 Research Methods
Psychology is first and foremost a science.
It is Empirical. It is based on research.
Before we delve into how to do research,
you should be aware of three hurdles that
tend to skew our logic.
Hindsight Bias
Hindsight bias is the tendency to think that past events were more predictable
than they actually were.
Knowing about hindsight bias is useful in two ways:
Firstly, it gives you something to say when your parents accuse you of failing to
predict an event. You can accuse him of having hindsight bias.(Well, it's better
than saying "Yeah, we know that now!")
Overconfidence
We tend to think we know more than we do
The Barnum Effect
• It is the tendency for
people to accept very
general or vague
characterizations of
themselves and take
them to be accurate.
Hawthorne Effect
• Just knowing you are participating in a
study can change the outcome.
Just the fact that you know you are in an experiment can cause change.
http://www.propagandaposters.us/poster11.html
Experimenter Bias
• “Did you study for
your test?”
• “MMMM.. I think
he wants me to
say yes?!?”
Terms used in Research:
Hypothesis: is a testable prediction that lets us
accept, reject or revise a theory.
If families do not stress gender differences then there will be fewer sex differences in siblings.
http://www.google.com/imgres?imgurl=http://www.simplypsychology.pwp.blueyonder.co.uk/hypothesis.jpg&imgrefurl=http://www.simp lypsychology.pwp.blueyonder.co.uk/aimshypotheses.html&usg=__NRh_zDntHhH4hvdURWKWFOXauEI=&h=384&w=428&sz=19&hl=en&start=0&zoom=1&tbnid=toLUNv3BSvDUhM:&tbnh=123&tbnw=137&prev=/images%3Fq%3Dhypothesis%26um%3D1%26hl%3Den%26sa%3DN%26rlz%3D1T4ADRA_enUS376US377%26biw%3D1899%26bih%3D922%26
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Theory
•Aims to explain
http://www.youtube.com/watch?v=cbEKAwCoCKw
• Experimental Group:
Receives Treatment
• Control Group:
receives no treatment
Operational Definitions
• Explain what you mean
in your hypothesis.
• How will the variables
be measured in “real
life” terms.
• How you
operationalize the
variables will tell us if
the study is valid and
reliable.
Let’s say your hypothesis
is that chocolate causes
violent behavior.
• What do you mean by
chocolate?
• What do you mean by
violent behavior?
Variables
http://tytusblog.blogspot.com/2009/08/engineers-make-better-models-of.html
are what you are manipulating in
your experiment.
• Placebo: “sugar pill” that is
given and the patient
believes to be the real thing.
SHHHHHHH
This lady thinks she
has been given and
antidepressant but
really she only got a
placebo.
Independent Variable
• Whatever is being
manipulated in the
experiment.
• Hopefully the
independent variable
brings about change.
If there is a drug in an
experiment, the drug
is almost always the
independent variable.
Dependent Variable
• Whatever is being
measured in the
experiment.
• It is dependent on the
independent variable.
The dependent variable
would be the effect
of the drug.
Beware of
Confounding Variables
If I wanted to prove that
smoking causes heart
issues, what are some
confounding variables?
• The object of an
experiment is to prove
that A causes B.
• A confounding variable
is anything that could
cause change in B, that
is not A.
Lifestyle and family
history may also
effect the heart.
Double Blind vs. Single Blind
Types of Research Methods
Types of Correlation
Positive Correlation
• The variables go in
the SAME direction.
Negative Correlation
• The variables go in
opposite directions.
Studying and
grades hopefully
has a positive
correlation.
Heroin use and
grades probably has
a negative
correlation.
Statistics
• Recording the
results from our
studies.
• Must use a common
language so we all
know what we are
talking about.
Descriptive Statistics
• Just describes sets
of data.
• You might create a
frequency
distribution.
• Frequency polygons
or histograms.
Validity and Reliability
•Valid:it is accurate
• Reliable:
It can be replicated
Central Tendency
• Mean, Median and Mode.
• Watch out for extreme scores or outliers.
Let’s look at the salaries of the
employees at Dunder Mifflen Paper
in Scranton:
$25,000-Pam
$25,000- Kevin
$25,000- Angela
$100,000- Andy
$100,000- Dwight
$200,000- Jim
$300,000- Michael
The median salary looks good at
$100,000.
The mean salary also looks good at
about $110,000.
But the mode salary is only $25,000.
Maybe not the best place to work.
Then again living in Scranton is kind
of cheap.
Normal Distribution
• In a normal
distribution, the
mean, median and
mode are all the
same.
Distributions
• Outliers skew
distributions.
• If group has one high
score, the curve has a
positive skew
(contains more low
scores)
• If a group has a low
outlier, the curve has
a negative skew
(contains more high
scores)
Other measures of variability
• Range: distance from
highest to lowest
scores.
• Standard Deviation:
the variance of scores
around the mean.
Shaq and Kobe may both
score 30 ppg (same mean).
• The higher the
variance or SD, the But their SDs are very
different.
more spread out the
distribution is.
• Do scientists want a
big or small SD?
Scores
• A unit that measures
the distance of one
score from the
mean.
• A positive z score
means a number
above the mean.
• A negative z score
means a number
below the mean.
Experimental vs. Control Group
Pg. 40
Self-Fulfilling Prophesy
http://www.youtube.com/watch?v=nOSNGKYKgX4
Methods of
Research
Types of Research
• Descriptive
• Correlational
• Experimental
Experimental Method
pg. 39
http://www.youtube.com/watch?v=6EjJsPylEOY
• Done in a lab.
• Good: You have control over your environment.
Naturalistic Observation
The
bad
is
that we can never
really show cause
and effect.
http://www.youtube.com/watch?v=fSiWXkOfHBY&feature=related
Good:
Let’s you
observe in a
participants natural
setting. There is
Hawthorne effect.
http://www.youtube.com/watch?v=e66XKxT8yDY
Case Studies
An intense study of a person or group. Diaries,
Tests, and interviews.
The Case Study
• Where one person (or situation) is
observed in depth.
What are the strengths and weaknesses of using a tragedy like
the Columbine School Shootings as a case study?
Survey Says…
http://www.youtube.com/watch?v=iejf3YZboQ8
• We like Survey’s because:
– 1. They are cheap
– 2. you can get a large amount of
information quickly.
We don’t like Survey’s
because:
1. Danger of participants
putting the wrong answers.
Survey Method: The Bad
• Low Response
Rate
• People Lie or
just
misinterpret
themselves.
• Wording
Effects
How accurate would a survey be about
the use of drugs in school?
Why do we sample?
• One reason is the False Consensus
Effect: the tendency to overestimate
the extent to which others share our
beliefs and behaviors.
Sampling
• SAMPLE is a group of
participants that
represent a POPULATION
six-sigma-material.com
http://mips.stanford.edu/courses/stats_data_analsys/lesson_1/234_0_a.html
A BAD SAMPLE
Finding the average height
of men or women by using
basketball players for your
sample.
Longitudinal Studies
http://www.google.com/imgres?imgurl=http://www.cfr.nichd.nih.gov/images/children_linedup2.jpg&imgrefurl=http://www.cfr.nichd.nih.gov/longitudinal.html&usg=__w_lHT2
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59
Data is taken from a group over a period of time.
Cross-Sectional Studies
• Data is collected from groups of
individuals of different ages and
compared.
http://www.google.com/imgres?imgurl=http://goodhealth.freeservers.com/Indonesia_kids_smoking.jpg&imgrefurl=http://snusnews.blogspot.com/2009_06_07_archive.html&usg=__oeZOXLzTwb1zO0kgdosS5qe_rCU=&h=351&w=468&sz=29&hl=en&start=132&zoom=1&t
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http://www.google.com/imgres?imgurl=http://www.lindsayheller.com/wp-content/uploads/2010/01/cigar_smoking_oldladies_0.jpg&imgrefurl=http://www.lindsayheller.com/%3Fpaged%3D11&usg=__FkMm0dRST9c9tJNK7B_LT22sqOE=&h=580&w=704&sz=70&hl=en&s
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http://www.google.com/imgres?imgurl=http://www.babble.com/CS/blogs/strollerderby/image141306x.jpg&imgrefurl=http://www.babble.c
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Correlational Research
• The correlation technique
indicates the degree of
association between 2
variables
• Correlations vary in direction:
– Positive association: increases in the
value of variable 1 are associated with
increases in the value of variable 2
– Negative association: increases in the
value of variable 1 are associated with
decreases in the value of variable 2
– No relation: values of variable 1 are
not related to variable 2 values
© 2004 John Wiley & Sons, Inc.
Huffman: PSYCHOLOGY IN ACTION,
7E
Correlation
pg. 39
The measure of a relationship between
two variables
=
This would be a positive correlation
• Correlation
• Weight Gain
Drinking Café
Mochas from
Dakotas everyday
=
This would be a negative correlation
Correlations
• Correlations also vary in the strength
of the association
– Zero correlation: no relationship
between the 2 variables
– Strong correlation: knowing the value of
one variable permits one to accurately
estimate the value of the other variable
• Strong correlation can be positive or negative
• Correlations can be seen in scatter
plots
© 2004 John Wiley & Sons, Inc.
Huffman: PSYCHOLOGY IN ACTION,
7E
Correlation Difficulties
© 2004 John Wiley & Sons, Inc.
Huffman: PSYCHOLOGY IN ACTION,
7E
Correlational Research
• Detects relationships between
variables.
• Does NOT say that one variable causes
another.
There is a positive correlation
between ice cream and
murder rates. Does that
mean that ice cream causes
murder?
Measured using a correlation
coefficient.
• A statistical measure of the extent to
which two factors relate to one another
How to Read a Correlation Coefficient
Why do we have
Ethical Guidelines?
During WWII the Nazi’s conducted some
very unethical studies. Many of their
subjects died during theses experiments.
What you need to know is:
1. These people were denied the
principles in the Belmont Report including
being asked to participate.
• Milgram Study (1963): The Milgram study
involved instructing subjects to administer
electric shocks to a study confederate in
response to poor performance. The subject
believed that he/she was involved in a study
about learning and memory with each shock
intended to affect the learning process. The
confederate pretended to be hurt by the
shock - in some cases, to the point of losing
consciousness; however, he/she did not
really feel any shock. The study objective
was to assess obedience to authority. This
study resulted in significant psychological
stress for some subjects including sweating,
trembling, stuttering and serious seizures in
three subjects. However, in a postexperimental interview, about half of the
subjects expressed that they were glad to
have participated in the experiment. The
question of whether this study was ethical
remains open to debate among scholars
today.
• Stanford
Experiment
• A group of men
volunteered for a
study and were
given the roles of
prisoners or
guards. In a short
time the guards
took it upon
themselves to start
trouble with the
prisoners and the
experiment got out
of hand. Lesson in
“the Lucifer”
Effect. How good
guys turn bad.
Ethical Issues in Research
• Respecting the rights of human research
participants involves:
– Informed consent is an explanation of a study and the
responsibilities of experimenter and participant
– Deception involving the subjects must be justified
– Confidentiality of study information must be maintained
– Debriefing refers to explaining the research process to
the subjects at the end of the study
• Animal research must be justified and must
minimize discomfort to participants
© 2004 John Wiley & Sons, Inc.
Huffman: PSYCHOLOGY IN ACTION,
7E
• Who has to approve ALL
research???
•IRB
• Institutional Review Board
(IRB)
Statistics
• A branch of math that summarizes and makes
meaningful inferences from the data.
http://www.google.com/imgres?imgurl=http://pix.motivatedphotos.com/2009/8/26/633868570471027490STATISTICS.jpg&imgrefurl=http://www.motivatedphotos.com/%3Fid%3D34720&usg=__v2u198pP5mA5uxBs2v5cCmV4Szo=&h=600&w=800&sz=70&hl=en&start=70&zoom=1&
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Normal Distribution
 Mode
Statistics
 the most frequently occurring score in a
distribution
 Mean
 the arithmetic average of a distribution
 obtained by adding the scores and then
dividing by the number of scores
 Median
 the middle score in a distribution
 half the scores are above it and half are
below it
Statistics
 Range
 the difference between the highest and
lowest scores in a distribution
 Standard Deviation
 a computed measure of how much scores
vary around the mean
 Statistical Significance
 a statistical statement of how likely it is that
an obtained result occurred by chance
Illusory Correlations
• Redelmeier and Tversky (1996) assessed 18
arthritis patients over 15 months, while also
taking comprehensive meteorological data.
Virtually all of the patients were certain that
their condition was correlated with the
weather.
• In fact the actual correlation was close to
zero.
• Usually when the data in question stands
out
• Ice cream sales and the number of
shark attacks on swimmers are
correlated.
• Skirt lengths and stock prices are highly
correlated (as stock prices go up, skirt
lengths get shorter).
• The number of cavities in elementary
school children and vocabulary size are
strongly correlated.