How Psychologists Learn
Scientific Methods
Announcements
Prometheus
The Psychology Department
at Rice University is sponsoring a Summer Research Internship
program in cognitive neuroscience for undergraduates beginning
June 9, 2003. The information can be found at the following
website:
http://psych.rice.edu/sicn/
Research Methods in Psychology
Naturalistic observations
Case studies
Tests, questionnaires, surveys
Experiments
Experiments
Controlled investigations
that study cause-effect relations through the manipulation of
variables.
Independent variable: What
the experi-menter manipulates to change or influence behavior.
Dependent variable: What the
experimenter measures.
Examples
Effects of television violence on aggressive behavior in children.
One group of children watches
an episode of Xena: Warrior Princess
Another group of children
watches an episode of Barney & Friends.
Later, children are allowed
to play freely; incidents of aggressive behavior are counted.
Examples
Effect of number of bystanders
on willingness of someone to seek help.
Each participant is placed
in a room that gradually starts to fill with smoke.
One group of participants
placed in room with no other people.
Another group of participants
placed in room with 3 other people.
Measure the amount of time
that passes before the participant seeks help.
Issues in Experiments
Experimental vs. control groups
Independent variable must
have at least 2 levels
Conclusions always relative
Confounding variables
Internal validity
Random assignment
Expectancy effects
Deception
Single-blind study
Double-blind study
External validity
Strengths & Weaknesses
+Precise control
+Strongest inferences about cause and effect
-Generalizability to individuals or real-world situations
may be limited
Example of an Experiment
If your Social Security Number
ends in 0, 1, or 2, you are in Group A.
If your Social Security Number
ends in 3, 4, 5, or 6, you are in Group B.
If your Social Security Number
ends in 7, 8, or 9, you are in Group C.
Questions
What is the independent variable?
What is the dependent variable?
How could this experiment
be improved?
Were experimental and control
groups used?
Was assignment to groups random?
Can you think of any confounding
variables?
Is expectancy likely to affect
outcomes?
Will these results generalize
to the real world?
Ethics of Psychological Research
Informed Consent
People must be informed about
any factors that may affect their willingness to participate (example).
Deception is allowed only
if it is necessary and the scientific value is clear; deception
may not cause harm or affect willingness to participate.
Debriefing
Confidentiality
Ethics of Animal Research
Why use animals?
Experimental control (e.g.,
life span development)
Only way to study some phenomena
(e.g., neurophysiology of learning; neural plasticity)
Is animal research ethical?
Is animal research necessary?
Has animal research been valuable?
Do animals suffer?
Oversight
All research with humans and
animals must be approved in advance by University review committees
(IRB).
Summary
The major research methods
used in psychology are naturalistic observation, case studies,
surveys, and experiments.
Each has advantages and disadvantages,
but experiments provide the best information about cause-effect
relations.
Psychological research is
governed by a strict code of ethics that protects the well-being
of human and animal participants.