Transcript File

INTRODUCTION
TO RESEARCH
PSYCHOLOGY AS A SCIENCE
The Study of Psychology
• Psychology is the scientific study of behavior
and mental processes
• Psychology values empirical evidence
• Psychology employs critical thinking
• Psychology employs systematic research
methods
© 2004 John Wiley & Sons, Inc.
Huffman: PSYCHOLOGY IN
ACTION, 7E
ALWAYS QUESTION THE ANSWERS
 Critical Thinking
 thinking that does not
blindly accept
arguments and
conclusions
 examines assumptions
 discerns hidden values
 evaluates evidence
The Amazing Randi--Skeptic
Barriers to Critical Thinking
 Hindsight Bias
 we tend to believe, after learning an outcome, that we
would have foreseen it
 the “I-knew-it-all-along” phenomenon
 Overconfidence
 we tend to think we know more than we do
 False Consensus Effect
 tendency to overestimate the extent to which others
share our beliefs and behaviors
The Need for Psychological
Science: Psychologists, like all scientists,
use the scientific method
PSYCHOLOGY AND THE
SCIENTIFIC METHOD
 Theory
 an explanation using an integrated set of
principles that organizes and predicts
observations
 Hypothesis
 a testable prediction
 often implied by a theory
The Need for Psychological
Science
 Replication
 repeating the essence of a research
study to see whether the basic finding
generalizes to other participants and
circumstances
 usually with different participants in
different situations
You Want to Study Something?
Make it SPECIFIC and
MEASURABLE!
 Operational Definition
 a statement of procedures (operations)
used to define research variables
 a measureable description of a construct
 Example intelligence may be operationally defined as what
an intelligence test measures (IQ score)
Operational Definitions
Operationalize the following constructs:
-
Age
Weight
Academic performance
Happiness
Relationship with parents
Descriptive Study
• Describes a set of facts
• Does not look for relationships between facts
• Does not predict what may influence the facts
• May or may not include numerical data
• Example: measure the % of new students from
out-of-state each year since 1980
Descriptive Design
 Naturalistic Observation
 observing and
recording behavior
in naturally
occurring
situations without
trying to
manipulate and
control the
situation
Description
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?
Data Collection: Surveys
Surveys are instruments designed to sample
attitudes or behaviors
technique for ascertaining the self-reported
attitudes or behaviors of people
usually by questioning a representative,
random sample of people
Example: asking persons at a rally how they
feel about animal rights issues
Population/Sample
Population: The large group
being studied (ex: American
teenagers)
Sample: The smaller group drawn from the
population (ex: 1000 teenagers from 9 urban
and rural cities)
POPULATION/SAMPLE
WHO DO YOU WANT TO STUDY?
Create three examples of population.
HOW WOULD YOU STUDY EACH?
Create examples of samples for each.
Psychological Research
•
WHERE?
Setting - field vs. laboratory
•
WHO?
Population/Sample
•
WHAT?
Research design
• descriptive, correlational, or experimental
•
HOW?
Data collection: self-report vs. observational
Identify the appropriate setting, design, and data collections for:
- Teenagers’ interactive patterns
- The effects of a new drug for depression
- The connection between marriage and happiness
Research Design #2:
Correlation
• Collects a set of facts organized into two or more
categories
• measure parents’ disciplinary style
• measure children’s behavior
• Examine the relationship between categories
• Correlation reveals relationships among facts
• The higher the discipline rates among parents, the lower the
behavioral problems by their children
Correlation
Height and Temperament of 20 Men
Height in
Subject Inches Temperament
1
2
3
4
5
6
7
8
9
10
80
63
61
79
74
69
62
75
77
60
75
66
60
90
60
42
42
60
81
39
Height in
Subject Inches Temperament
11
12
13
14
15
16
17
18
19
20
64
76
71
66
73
70
63
71
68
70
48
69
72
57
63
75
30
57
84
39
Correlation
95
Temperament 90
scores 85
80
75
70
65
60
55
50
45
40
35
30
25
55
60
65
70
Height in inches
75
Scatterplot of Height and Temperament
80
85
Correlation: Scatterplots
 Scatterplot
 a graphed cluster of dots, each of which represents the values
of two variables
 the slope of the points suggests the direction of the
relationship
 the amount of scatter suggests the strength of the correlation
 little scatter indicates high correlation
 also called a scattergram or scatter diagram
Correlation
Perfect positive
correlation (+1.00)
No relationship (0.00)
Perfect negative
correlation (-1.00)
Scatterplots, showing patterns of correlations
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
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)
Correlational Design:
Limitations
• 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
well behaved children
Correlation:
Is there a relationship
between self-esteem and depression?
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
Types of Research
Design
Differentiating Research Methods