RESEARCH
METHODS
Psychology Chapter 2
Goals of Psychology
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•
•
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Describe
Explain
Predict
Control
………behavior and mental processes
Critical Thinking
1. Thinking that does not blindly
accept arguments or conclusions
but questions their validity
The opposite is NOT THINKING
(willingly accepting the most
simple explanation).
Why is Research
Important?
Research and Research Methodology
1. Method of asking questions then
drawing logical supported
conclusions based on facts
2. Researchers need to be able to
determine if their conclusions are
reasonable or not (critical thinking).
Scientific Method
1. Technique using tools such as
observation, experimentation, and
statistical analysis to learn about
the world
2. Through its use, psychology is
thereby considered a science.
Steps to the Scientific Method
1.
2.
3.
4.
5.
6.
Form a research question
Develop a hypothesis
Test hypothesis
Analyze data / results
Draw a conclusion
Report results
–
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Publication
Replication
Theory
1. Tentative explanation for observed
findings
– Uses results from individual studies
– Tool for explaining observed behavior
2. Theories can change as new scientific
evidence is found.
3. Analogy: Prosecuting Attorney presents
their theory backed up by evidence to the
jury.
Common Sense
1. Conclusions based solely on
personal experience and sensible
logic
2. Most of the time it is good
but…can lead to incorrect
conclusions
Did You Know…
• It is nearly impossible to fold a regular
sheet of paper in half more than 8 times.
• Go ahead and try!
• Mythbusters pulled it off with a piece of
paper as big as an airplane hanger and a
steam roller.
Science vs. Common Sense
1. Science helps build explanations that
are consistent and predictive as
opposed to conflicting and describing
the past (hindsight)
2. Science is based on
–
–
–
–
knowledge of facts
developing theories
testing hypotheses
public and repeatable procedures
Hindsight Bias
1. The tendency to exaggerate one’s ability to have foreseen
how something would turn out after learning the outcome.
2. The “I knew it all along” phenomenon.
– Week before the 1985 Super Bowl, 81% of students in a Stanford
Psychology class predicted the Miami Dolphins would win. 40%
said the Dolphins would win by 10 or more points.
– A week after San Francisco 49ers decisive victory, he asked the
group who picked the 49ers.
• 58% said they picked the 49ers
• NO ONE remembered saying the Dolphins would win by at
least 10 points.
Overconfidence
1. Tendency to overestimate the accuracy of
our current knowledge
2. We are more confident than we are correct.
3. Overconfidence in ourselves can lead us to
say dumb things:
– “Man will never reach the moon, regardless
of all future scientific advances.” - Lee
DeForest, inventor of vacuum tube, 1957
REVIEW QUESTION
What is the difference between
Common Sense and Science?
ANSWER:
Common sense relies on the past and may be
wrong.
Science uses facts to provide consistent predictions
DO YOU AGREE OR DISAGREE?
Bias
A Researcher’s Worst Enemy
WHY????
Bias
1. Situation in which a factor unfairly
increases the likelihood of a
researcher reaching a particular
conclusion
2. Bias should be minimized as much
as possible in research
Confirmation Bias
• Our tendency to search for
information that confirms our beliefs
and ignore those that don’t.
Researcher Bias
• The tendency to notice evidence
which supports one particular point of
view or hypothesis
Volunteer Bias
• People who volunteer to participate in a survey
differ from those who do not.
• Those who complete it are often willing to share,
have similar interests, have spare time (magazine
surveys).
• These factors skew or slant the results.
• Eliminate this by using a random sample where
everyone has equal chance of being chosen to
participate.
Participant Bias
• Tendency of research subjects to respond in
certain ways because they know they are being
observed
– Do you act the same in the classroom as you do at
home?
• The subjects might try to behave in ways they
believe the researcher wants them to behave
• Can be reduced by naturalistic observation
Research Strategies
Surveys
Observations
Experiments
Research Strategies Fall Into 2
Categories
• Descriptive—strategies for observing and
describing behavior
– Observation
– Surveys
• Experimental—strategies for inferring
cause and effect relationships among
variables
Example from August 9
Question: Can we make any
determinations about these scores?
• 2nd Period survey on
“what you know about
psychology”
• Average: 45.78
• Low= 28
• High= 59
• 4th Period survey on
“what you know about
psychology”
• Average: 46.50
• Low= 21
• High=57
Longitudinal and
Cross-Sectional
Studies
Developmental Psychologists
• Psychologists who study how
individuals change throughout their
lifetime
• These psychologists use longitudinal
& cross-sectional studies
Longitudinal Study
• Researchers study the same group of
individuals for many years to see how
they change.
• Can be very expensive and difficult to
conduct
• Risky – people may drop out
Cross-Sectional Study
• Researchers simultaneously study a
number of subjects from different age
groups and then compare the results to see
how they are different.
• Cheaper, easier than longitudinal studies,
but group differences may be due to
factors other than development. (More
variables.)
Longitudinal/Cross Sectional
Study
Naturalistic Observation
• Method of observation where subjects are
observed in their “natural” environment
• Subjects are not aware they are being
watched – researcher does not interfere
• Could use hidden cameras or two way
mirrors
• Ex: People eating in a restaurant
Laboratory Observation
• Not always a sterile room.
• Place where the environment can be controlled
to minimize the number of variables.
• Negatives are that it may cause the subject to
act differently than it normally would.
• Ex: Skinner Box, maze, fish tank
Case Study
• In depth study of one individual with the hopes of
determining universal principles
• Generally used to investigate rare, unusual, or
extreme conditions
– Example: Phineas Gage
Negatives:
• This technique is very open to bias
• Difficulty of applying data from one person to
everyone
Survey Method
• Research method that relies on selfreports; uses surveys, questionnaires,
interviews.
• Usually a very efficient and
inexpensive method
• Can you guess some limitations of
this method of research?
Survey Limitations
• Accuracy is a concern; people are not always
honest.
• They fear confidentiality or want to please the
researcher.
• Example: Tooth brushing survey in 1960s. If as
many people actually brushed their teeth as often
as they claimed to brush their teeth, 33% (?) more
toothpaste would have been sold that year.
Sampling Terms
• (Target) Population—large (potentially infinite)
group represented by the sample. Findings are
generalized to this group.
• Sample—selected segment of the population for
the study
• Stratified or Representative sample—closely
parallels the target population on relevant
characteristics; sample is proportional to
TARGET POPULATION
• Random selection—every member of larger
group has equal chance of being selected for the
study sample
Random Sample
• A sample that represents the target
population:
– Each member of the population has an equal
chance of being included.
– If a sample is not random it is said to be
biased.
– Increase chances of representing population
when sample is BIG ENOUGH
– How would you pick a random sample???
Generalizing the Results
• Applying the findings from the research
group to other groups.
• Be cautious about generalizing when it isn’t
a random or stratified sample.
• Example: Car preference differs between
men, women, region, socio-economic
background, and more.
Correlational Study
• Examine the relationship of how closely one
thing is related to another
• Collects a set of facts organized into two or
more categories
– measure parents’ disciplinary style
– measure children’s behavior
• Correlation reveals relationships among facts
– e.g., more democratic parents have children who behave
better
• Correlational studies are helpful in making
predictions.
Correlational Study
• Does NOT determine a cause and effect relationship between the
variables
• Correlation CANNOT prove causation
– Do democratic parents produce better behaved children?
– Do better behaved children encourage parents to be democratic?
• May be an unmeasured common factor
– e.g., good neighborhoods produce democratic adults and wellbehaved children
• Does NOT determine why the two variables are related--just that they
are related.
Zero Correlation
• There is no relationship at all between
the two variables.
How to Read a Correlation
Correlation & Causation
• There is a strong +.90 correlation in shoe
size and IQ.
• Does this mean that a large shoe size is the
cause for higher intelligence?
• What else could explain this?
•YOUR FEET GROW
AS YOU GET OLDER &
WISER
Let’s Review
Experimental Method
The Only Way to Show
Cause & Effect
Experimental Terms
1. Variable – part of experiment that changes
2. Independent Variable (IV)– controlled by
researcher. This variable causes
something to happen.
3. Dependent Variable (DV) – watched by
the researcher to see the impact of the IV.
This variable is the effect that is caused by
the IV.
Groups
1. Experimental group – receives the treatment;
frequently a drug
2. Control group – receives no treatment; usually
receives a placebo (fake drug)
3. “Placebo Effect” – participants react because they
THINK they are receiving treatment (sugar pill)
–
Mind over Matter
4. “Nocebo” – If told a drug won’t work, the person will
feel it doesn’t work even if it is a legitimate drug.
Eliminating Bias
• Single Blind Study – Participants do not know if
they are receiving the treatment of the placebo
• Double Blind Study – Neither the participants
nor the researchers know if they are administering
the treatment or the placebo.
Limitations of Experiments
• Conditions in an experiment may not reflect
conditions of real life.
• (Must simplify variables to get useful
information.)
• Ethical considerations in creating some
more “real life” situations
Research Ethics
• Confidentiality – participants are more
likely to be truthful if they know their
privacy is protected. Confidentiality can be
broken if information reveals harm to
another person
Ethics
• Informed consent – some studies may have long
term threats or irreversible effects.
– Participants must be given a choice to participate after
being informed of the study.
• Deception— is allowable when benefit
outweighs harm and participants receive full
explanation at its conclusion
Animal Research
• APA has rules for animals, too.
• Often used instead of humans when topic could
not be ethically studied on a human.
– Ex: Early separation studied by Harlow in 1959 with
monkeys.
• Animal experiments lead to solutions with
humans – eating disorders, drug treatments
• Still controversial due to the fact that animals can
be harmed in studies.