Transcript Introduction to Psychology

Chapter 2
The Research Enterprise in
Psychology
Critical Thinking
Be an informed
consumer!
This is a
business!!!
$$$$$
Critical Thinking
Thinking that does not blindly
accept arguments and
conclusions
examines assumptions
discerns hidden values
evaluates evidence
Common pitfalls
 Misconceptions
 Anecdotal evidence
 Hindsight bias
“I knew it all along” phenomenon
 Overconfidence
“They couldn’t hit an elephant at
this dist---” last words
The Research Enterprise
What are the goals of
the scientific
enterprise?
Goals of the scientific
enterprise
1. Measurement and
description
2. Understanding and
prediction
3. Application and control
Key terms
1. Hypothesis
Tentative statement
about two variables
2. Theory
system of ideas
Steps in a scientific investigation
1. Formulate a testable
hypothesis
2. Select the research
method and design
the study
Steps in a scientific investigation
3. Collect the data
4. Analyze the data and
draw conclusions
5. Report the findings
Research Methods
 Operational Definition
 a statement of procedures (operations)
used to define research variables
 Example depression operationally defined in the
Diagnostic and Statistical Manual (DSM)
Replication
 Repeating the essence of a
research study
 One use of operational
definitions is for replication
Generalizability
 Investigating whether findings
extend to other populations
Key terms
 Population
 all the cases in a group, from which
samples may be drawn for a study
(for example, high school students)
 Sample
 Participants in your study (students
in this class)
False consensus effect
 Overestimating the extent to which
others share our beliefs and
behaviors
 Example: If we sit on the Palmetto
sidelines we’ll hear “Filet the fish.”
Do coral reef fans say that?
Random sample
 A representative
group
 Each member has
an equal chance of
inclusion
 If marbles of two
colors are mixed well
in the large jar,
transfer a few into a
smaller one and
count them
Research Methods
1. Experiment
2. Naturalistic observation
3. Case studies
4. Surveys
Case study
Psychologists
study one or
more individuals
in great depth in
the hope of
revealing things
true of us all
Is language uniquely human?
Survey
 technique for ascertaining the
self-reported attitudes or
behaviors of people
 usually by questioning a
representative, random sample of
people
 questionnaire
Naturalistic Observation
observing and
recording behavior
in naturally
occurring situations
without trying to
manipulate and
control the situation
Experimentation
An investigator manipulates one or more
factors (independent variables) to
observe their effect on some behavior or
mental process (the dependent variable)
Experimentation

Independent Variable



the experimental factor that is manipulated
the variable whose effect is being studied
Dependent Variable


the outcome
“depends on the independent variable”
Experimentation

Extraneous variables



Confound
Influences the dependent variable
To reduce extraneous variables


Control group
Random assignment
Experimentation
 Experimental Condition
 the condition of an experiment that exposes
participants to the “treatment”
 Control Condition
 the baseline or no “treatment”
Experimentation
 Random Assignment
 assigning participants to
experimental and control conditions
by chance
 minimizes pre-existing differences
between those assigned to the
different groups
Experimentation
Pretest
Posttest
Group 1
(flashcards)
10%
100%
Group 2
(no flashcards)
10%
30%
Identify the
Experimental condition
Control condition
Independent variable
Dependent variable
Identify the
Experimental condition
Flashcards
Control condition
No flashcards
Independent variable
Study technique
Dependent variable
Test scores
Experimentation
 Random Assignment
 assigning participants to
experimental and control conditions
by chance
 minimizes pre-existing differences
between those assigned to the
different groups
DO NOT CONFUSE
Random Sampling
versus
Random Assignment
Experimentation
 Placebo group
 Receives no active ingredient
 Placebo effect
 Control group received no active
ingredient
 Change in this group due to
expectations
Experimentation
 Double-blind procedure
 Both the researchers and the
participants are “blind” to the
treatment received
 Example: glaucoma study
Experimentation
 Only method permitting claims of
cause and effect
 CORRELATION ALONE
IS NOT CAUSALITY!
Correlation
 Correlation Coefficient
 a statistical measure of the extent to which two factors vary
together, and thus how well either factor predicts the other
Indicates direction
of relationship
(positive or negative)
Correlation
coefficient
r = +.37
Indicates strength
of relationship
(0.00 to 1.00)
Correlations
Positive versus negative correlations
 Positive = as one variable
increases so does the other
 Negative = as one variable
increases
The other decreases
Strength of correlation
 Correlations range from -1 to +1
 A larger number indicates a
stronger relationship between the
two variables
 Zero correlation = no relationship
Correlation
Perfect positive
correlation (+1.00)
No relationship (0.00)
Perfect negative
correlation (-1.00)
Scatterplots, showing patterns of correlations
Correlation
Three Possible Cause-Effect Relationships
(1)
Low self-esteem
could cause
Depression
or
(2)
Depression
could cause
Low self-esteem
or
Low self-esteem
(3)
Distressing events
or biological
predisposition
could cause
and
Depression
Statistical Reasoning
 Mode
 the most frequently occurring score in a
distribution
 Mean
 The average
 Median
 the middle score in a distribution
 half the scores are above it and half are below it
Statistical Reasoning
 Range
 the difference between the highest and lowest
scores in a distribution
 Variability
 how much the scores vary
 Standard Deviation
 a computed measure of how much scores vary
around the mean
Statistical Reasoning
 Statistical Significance
 a statistical statement of how likely it is that an
obtained result occurred by chance
 “significant” has a very particular meaning to
psychologists
Ethics in research
 Informed consent
 Internal review board (IRB)
 Deception and debriefing
 Animal research
Study aids
 Concept checks
 Featured study*
 Recap
 Practice test
 Textbook website
Featured Study
Can subliminal audiotapes
improve memory or selfesteem?
Featured Study
Be able to answer the following
questions:
1. What was the hypothesis?
2. What did they do?
3. What did they find?
4. Why do we care?