1. Myers’ PSYCHOLOGY
(7th Ed)
Chapter 1
Thinking Critically with
Psychological Science
James A. McCubbin, PhD
Clemson University
Worth Publishers

2. The Need for
Psychological Science
Psychologists, like all scientists, use
the scientific method to construct
theories that organize observations
and imply testable hypotheses

3. The Need for
Psychological Science
 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

4. The Need for
Psychological Science
 Critical Thinking
 thinking that does not
blindly accept
arguments and
conclusions
 examines assumptions
 discerns hidden values
 evaluates evidence
The Amazing Randi--Skeptic

5. The Need for
Psychological Science
 Theory
 an explanation using an integrated set of
principles that organizes and predicts
observations
 Hypothesis
 a testable prediction
 often implied by a theory

6. The Need for
Psychological Science

7. The Need for
Psychological Science
 Operational Definition
 a statement of procedures (operations)
used to define research variables
 Example-
 intelligence may be operationally defined as
what an intelligence test measures

8. 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

9. Description
Psychologists describe behavior
using case studies, surveys, and
naturalistic observation

10. 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?

11. Description
 Survey
 technique for ascertaining the self-reported
attitudes or behaviors of people
 usually by questioning a representative, random
sample of people
 Random Sample
 a sample that fairly represents a population
because each member has an equal chance of
inclusion

12. Description
 False Consensus Effect
 tendency to overestimate the extent to
which others share our beliefs and
behaviors
 Population
 all the cases in a group, from which
samples may be drawn for a study

13. Description

14. Description
 If marbles of two
colors are mixed well
in the large jar, the
fastest way to know
their ratio is to blindly
transfer a few into a
smaller one and
count them

15. Description
 Naturalistic
Observation
 observing and
recording behavior
in naturally
occurring situations
without trying to
manipulate and
control the situation

16. 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
r = +.37
coefficient
Indicates strength
of relationship
(0.00 to 1.00)

17. Correlation
 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

18. Correlation
Perfect positive No relationship (0.00) Perfect negative
correlation (+1.00) correlation (-1.00)
Scatterplots, showing patterns of correlations

19. Correlation
Height and Temperament of 20 Men
Height in Height in
Subject Inches Temperament Subject Inches Temperament
1 80 75 11 64 48
2 63 66 12 76 69
3 61 60 13 71 72
4 79 90 14 66 57
5 74 60 15 73 63
6 69 42 16 70 75
7 62 42 17 63 30
8 75 60 18 71 57
9 77 81 19 68 84
10 60 39 20 70 39

20. Correlation
95
Temperament
90
scores
85
80
75
70
65
60
55
50
45
40
35
30
2555 60 65 70 75 80 85
Height in inches
Scatterplot of Height and Temperament

21. Correlation
Three Possible Cause-Effect Relationships
could cause
(1)
Depression
Low self-esteem
or
(2) could cause
Low self-esteem
Depression
or
Low self-esteem
(3)
Distressing events could cause
and
or biological
predisposition
Depression

22. Illusory Correlation
 Illusory Conceive Do not conceive
Correlation confirming
evidence
disconfirming
evidence
Adopt
 the perception
of a
relationship disconfirming confirming
where none Do not
evidence evidence
exists adopt

23. Two Random
Sequences
 Your chances of
being dealt
either of these
hands is
precisely the
same: 1 in
2,598,960.

24. Experimentation
 Experiment
 an investigator manipulates one or more
factors (independent variables) to observe
their effect on some behavior or mental
process (the dependent variable)
 by random assignment of participants the
experiment controls other relevant factors

25. Experimentation
 Placebo
 an inert substance or condition that may be
administered instead of a presumed active agent,
such as a drug, to see if it triggers the effects
believed to characterize the active agent
 Double-blind Procedure
 both the research participants and the research
staff are ignorant (blind) about whether the
research participants have received the treatment
or a placebo
 commonly used in drug-evaluation studies

26. Experimentation
 Experimental Condition
 the condition of an experiment that exposes
participants to the treatment, that is, to one
version of the independent variable
 Control Condition
 the condition of an experiment that contrasts
with the experimental treatment
 serves as a comparison for evaluating the effect
of the treatment

27. Experimentation
 Random Assignment
 assigning participants to
experimental and control conditions
by chance
 minimizes pre-existing differences
between those assigned to the
different groups

28. Experimentation
 Independent Variable
 the experimental factor that is manipulated
 the variable whose effect is being studied
 Dependent Variable
 the experimental factor that may change in
response to manipulations of the independent
variable
 in psychology it is usually a behavior or mental
process

29. Experimentation

30. Research Strategies
Subliminal tape content
Self-esteem Memory  Design of the
Tape label subliminal
Self-esteem tapes
experiment
Memory

31. Statistical Reasoning
100%
Percentage
still functioning 99
after 10 years
98
97
96
95
Our Brand Brand Brand
Brand X Y Z
Brand of truck

32. Statistical Reasoning
100%
Percentage
90
still functioning
80
after 10 years
70
60
50
40
30
20
10
0
Our Brand Brand Brand
Brand X Y Z
Brand of truck

33. Statistical Reasoning
 Mode
 the most frequently occurring score in a
distribution
 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

34. Statistical Reasoning
A Skewed Distribution
15 20 25 30 35 40 45 50 90 475 710
70
Mode Median Mean
One Family Income per family in thousands of dollars

35. Statistical Reasoning
 Range
 the difference between the highest and lowest
scores in a distribution
 Standard Deviation
 a computed measure of how much scores vary
around the mean
 Statistical Significance
 a statistical statement of how likely it is that an
obtained result occurred by chance

36. Frequently Asked Questions
about Psychology
Can laboratory experiments
illuminate everyday life?

37. Frequently Asked Questions
about Psychology
Does behavior depend on
ones culture?
 Culture--the enduring behaviors,
ideas, attitudes, and traditions
shared by a large group of people
and transmitted from one
generation to the next

38. Frequently Asked Questions
about Psychology
Does behavior vary with
gender?

39. Frequently Asked Questions
about Psychology
Why do psychologists study
animals?
Is it ethical to experiment on
animals?
Is it ethical to experiment on
people?

40. Frequently Asked Questions
about Psychology
Is
psychology
free of
value
judgments?

41. Frequently Asked Questions
about Psychology
Is psychology potentially
dangerous?