Ch. 2 Research Methods

Ch. 2 Research Methods
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• Experiments
Terms used in Research:
• Hypothesis: we are moving from an
educated guess to expresses a
relationship between two variables.
A theory is a based upon a hypothesis and backed by evidence. A theory
presents a concept or idea that is testable. In science, a theory is not merely
a guess. A theory is a fact-based framework for describing a phenomenon.
Fun Theory:
• A theory Aims to explain
are what you are manipulating in
your experiment.
Independent variable
• The independent variable is the
characteristic of a psychology
experiment that is manipulated or
changed. For example, in an
experiment looking at the effects of
studying on test scores, studying
would be the independent variable.
Dependent Variable
• The dependent variable is the variable that
is being measured in an experiment. For
example, in a study on the effects of
tutoring on test scores, the dependent
variable would be the participants test
Let’s try some:
• Students watched a cartoon either alone
or with others and then rated how funny
they found the cartoon to be.
• Independent Variable:
• Dependent Variable:
Smithers thinks that a special juice will
increase the productivity of workers. He
creates two groups of 50 workers each
and assigns each group the same task
(in this case, they're supposed to staple
a set of papers). Group A is given the
special juice to drink while they work.
Group B is not given the special juice.
After an hour, Smithers counts how
many stacks of papers each group has
made. Group A made 1,587 stacks,
Group B made 2,113 stacks.
Identify the:
1. Control Group
2. Independent (Manipulated) Variable
3. Dependent (Responding) Variable
4. What should Smithers' conclusion be?
5. How could this experiment be improved?
Homer notices that his shower is
covered in a strange green slime. His
friend Barney tells him that coconut
juice will get rid of the green slime.
Homer decides to check this this out by
spraying half of the shower with
coconut juice. He sprays the other half
of the shower with water. After 3 days
of "treatment" there is no change in the
appearance of the green slime on either
side of the shower.
6. What was the initial observation?
Identify the7. Control Group
8. Independent (Manipulated) Variable
9. Dependent (Responding) Variable
10. What should Homer's conclusion be?
Bart believes that mice exposed to radiowaves will
become extra strong (maybe he's been reading too
much Radioactive Man). He decides to perform this
experiment by placing 10 mice near a radio for 5
hours. He compared these 10 mice to another 10
mice that had not been exposed. His test consisted
of a heavy block of wood that blocked the mouse
food. he found that 8 out of 10 of the radiowaved
mice were able to push the block away. 7 out of 10
of the other mice were able to do the same.
Identify the11. Control Group
12. Independent (Manipulated)
13. Dependent (Responding) Variable
14. What should Bart's conclusion be?
15. How could Bart's experiment be
Krusty was told that a certain itching powder
was the newest best thing on the market, it
even claims to cause 50% longer lasting
itches. Interested in this product, he buys
the itching powder and compares it to his
usual product. One test subject (A) is
sprinkled with the original itching powder,
and another test subject (B) was sprinkled
with the Experimental itching powder.
Subject A reported having itches for 30
minutes. Subject B reported to have itches
for 45 minutes
Identify the16. Control Group
17. Independent (Manipulated)
18. Dependent (Responding) Variable
19. Explain whether the data supports
the advertisements claims about its
Validity and Reliability
• Valid:
it is accurate
• Reliable:
It can be replicated
• Validity is the extent to which a test
measures what it claims to measure. It is
vital for a test to be valid in order for the
results to be accurately applied and
• Validity isn’t determined by a single
statistic, but by a body of research that
demonstrates the relationship between
the test and the behavior it is intended to
• Reliability refers to the consistency of
a measure. A test is considered
reliable if we get the same result
repeatedly. For example, if a test is
designed to measure a trait (such as
introversion), then each time the test
is administered to a subject, the
results should be approximately the
• Placebo: A placebo is a
substance with no known
medical effects.
This lady thinks she
has been given and
antidepressant but
really she only got a
Problems with Research
• We tend to think we know more than we do.
82% of U.S. drivers consider themselves to be in the top 30% of their group in terms of
81% of new business owners felt they had an excellent chance of their businesses
succeeding. When asked about the success of their peers, the answer was only 39%. (Now
that's overconfidence!!!)
Confirmation Bias
• A tendency for people to accept information
that confirms what they want believe
Psych335 - Confirmation Bias - Team 16
Hindsight Bias
The tendency to believe after the
outcome that you knew it all along.
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Scene: 3min.
Hawthorne Effect
• Just knowing you are participating in a
study can change the outcome. Pg. 43
Hawthorne effect
Experimenter Bias
Experimental bias is where the scientist or researcher doing the research
influences the results so that they can show a certain outcome.
• “Did you study for
your test?”
• “MMMM.. I think
he wants me to
say yes?!?”
Experimental vs. Control Group
Pg. 40
• Experimental Group:
Receives Treatment
• Control Group:
receives no treatment
Let’s try one
• Larry was told that a certain muscle cream was the newest
best thing on the market and claims to double a person’s
muscle power when used as part of a muscle-building
workout. Interested in this product, he buys the special
muscle cream and recruits Patrick and SpongeBob to help him
with an experiment. Larry develops a special marshmallow
weight-lifting program for Patrick and SpongeBob. He meets
with them once every day for a period of 2 weeks and keeps
track of their results. Before each session Patrick’s arms and
back are lathered in the muscle cream, while Sponge Bob’s
arms and back are lathered with the regular lotion.
• Which person is in the control group?
• What is the independent variable?
• What is the dependent variable?
A study was created to test the effects of jazz on people’s sleep patterns.
The hypothesis of the experiment was that if people listened to jazz music as
they fall asleep, they will sleep for longer periods of time. For the
experiment, 2 groups of people were created. One group was placed in a
quiet room where they went to sleep and they were timed on how long they
slept. The other group was placed in a room where jazz music played softly
as they began to sleep and played throughout the night. As each group
awoke, their sleep times were monitored.
Control Group:
Experimental group:
Independent Variable:
Dependent variable:
Double Blind vs. Single Blind
A double-blind study is one in which
neither the participants or the
experimenters know who is receiving
a particular treatment.
A single-blind study is one in which
experimenters know who is receiving a
particular treatment but the patient
does not.
Self-Fulfilling Prophesy
belief that becomes true because people act as though it is true.
Methods of
Types of Research
• Descriptive
• Correlational
• Experimental
Experimental Method
pg. 39
• Done in a lab.
• Good: You have control over your environment.
Naturalistic Observation
• involves observing subjects in their natural
Jane Goodall
Pg. 37
Good: Let’s you observe
in a participants natural
Naturalist Observation
BAD: you have to
avoid disturbing
what you are
Case Studies
An intense study of a person or group. Diaries,
Tests, and interviews.
Survey Says… it is a data collection
tool used to gather information about
• 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
1. Danger of participants
putting the wrong answers.
• SAMPLE is a group of
participants that
represent a POPULATION
Finding the average height of men or
women by using basketball players for
your sample.
Longitudinal Studies
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
Click me:
pg. 39
The measure of a relationship between
two variables
This would be a positive correlation
Correlation does not mean
• Detects relationships between
• Does NOT say that one variable causes
There is a positive correlation
between ice cream and
murder rates. Does that
mean that ice cream causes
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.
• Due to overcrowding, children were denied
entrance to the Willow brook State Mental
Hospital unless parents enrolled their
children into the less-crowded hepatitis
ward. Geraldo Rivera did a story on the
horrible conditions there. The children
were not clothed and forced to eat in three
minutes. It was horrible.
Tuskegee Syphilis Study: In
1932, the Public Health Service enrolled
several hundred syphilitic black males to
document the effects of the untreated
disease over time. Tuskegee was chosen
because approximately 40% of the male
population of the town was infected with
the disease. Treatment was withheld from
study subjects when penicillin was
accepted as the treatment for syphilis in
1943. This study was stopped in 1973 but
not before many subjects became seriously
ill, transmitted their disease to others or
died. This study exemplifies unfair subject
selection practices (syphilis can potentially
affect all human beings and is not limited
to African American males), denial of
informed consent and excessive risk in
relation to study benefits.
• 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
The Monster Study
• A Speech Experiment where Wendell
Johnson rounded up some orphans
and separated them into two groups.
The first group received positive
reinforcement all of the time. The
second group was constantly
critiqued. He wanted to see if they
would start stuttering.
• Stanford
• 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.
Stanford: The Lucifer Effect
• When Good People Do Bad Things, Part 2
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.
• Who has to approve ALL
• Institutional Review Board
• A branch of math that summarizes and makes
meaningful inferences from the data.
Normal Distribution
 Mode
 the most frequently occurring score in a
 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
Highest score from lowest score.
Let’s try one
, 66 ,102 , 114 , 78 , 90