PSYCHOLOGY
(8th Edition)
David Myers
PowerPoint Slides
Aneeq Ahmad
Henderson State University
Worth Publishers, © 2006
1
Thinking Critically with
Psychological Science
Chapter 1
2
The Need for Psychological Science
Intuition & Common Sense
Many people believe that intuition and common
sense are enough to bring forth answers regarding
human nature.
Intuition and common sense may aid queries,
but they are not free of error.
3
Limits of Human Intuition
Exercise
4
Limits of Intuition
Personal interviewers may
rely too much on their “gut
feelings” when meeting
with job applicants.
Taxi/ Getty Images
5
Hindsight Bias
Hindsight Bias is the “I-knew-it-all-along”
phenomenon.
After learning the outcome of an event, many
people believe they could have predicted that very
outcome. We only knew the dot.com stocks would
plummet after they actually did plummet.
6
Overconfidence Activity
• I feel 98 percent certain that the area of the U.S. is
more than ____ square miles but less than ____
square miles.
• I feel 98 percent certain that in 2003 the population of
Australia was more than ___ but less than ____.
• I feel 98 percent certain that the number of American
battle deaths in the Spanish-American War was more
than ___ but less than ___.
7
Overconfidence Activity
• I feel 98 percent certain that in 2002 the
number of female engineers in the United
States was more than ___ but less than
___.
• I feel 98 percent certain that in 2002 the
number of operating nuclear plants in the
world was more than ___ but less than
___.
8
Overconfidence
Sometimes we think we
know more than we
actually know.
How long do you think it
would take to unscramble
these anagrams?
People said it would take
about 10 seconds, yet on
average they took about 3
minutes (Goranson, 1978).
Anagram
WREAT
WATER
ETYRN
ENTRY
GRABE
BARGE
9
Overconfidence
Now try this word scramble!
Anagram
OCHSA
CHAOS
ICSCRU
CIRCUS
LPNTEEAH ELEPHANT
10
The Point to Remember
• Hindsight bias and overconfidence often
lead us to overestimate our intuition. But
scientific inquiry, fed by curious skepticism
and by humility can help us sift reality from
illusions.
11
Psychological Science
1. How can we differentiate between
uniformed opinions and examined
conclusions?
2. The science of psychology helps make
these examined conclusions, which leads
to our understanding of how people feel,
think, and act as they do!
12
The Scientific Attitude
The scientific attitude is composed of curiosity
(passion for exploration), skepticism (doubting
and questioning) and humility (ability to accept
responsibility when wrong).
13
Critical Thinking
Courtesy of the James Randi Education Foundation
Critical thinking does
not accept arguments
and conclusions blindly.
It examines
assumptions, discerns
hidden values,
evaluates evidence and
assesses conclusions.
The Amazing Randi
14
Scientific Method
Psychologists, like all scientists, use the
scientific method to construct theories that
organize, summarize and simplify
observations.
15
VIDEO
DISCOVERING
PSYCHOLOGY:
RESEARCH METHODS
Video link: http://www.learner.org/discoveringpsychology/02/e02expand.html
16
Theory
A Theory is an explanation that integrates
principles and organizes and predicts
behavior or events.
For example, low self-esteem contributes to
depression.
Theories are NOT the product of
guesswork! They are highly researched,
rigorously tested frameworks.
17
TROUBLESHOOTING
• NOTE: Our text does not use the term
generalizability. This term is used on the
AP EXAM. It refers to what degree the
results of a study can be applied to
different types of populations.
18
Hypothesis
A Hypothesis is a testable prediction, often
prompted by a theory, to enable us to
accept, reject or revise the theory.
People with low self-esteem are apt to feel
more depressed.
TROUBLESHOOTING: A hypothesis is
NOT an educated guess.
19
HYPOTHESIS
• In psychology, a hypothesis is a statement
of a relationship between or among
variables. (not in text)
20
Research Observations
Research would require us to administer
tests of self-esteem and depression.
Individuals who score low on a self-esteem
test and high on a depression test would
confirm our hypothesis.
21
Research Process
22
Operational Definitions
• To reduce bias psychologists report their
research with operational definitions.
• An operational definition states how the
variable is observed and measured. An
operational definition must be
manageable.
• Operational definitions allows others to
replicate (repeat) the observations. Why?
23
OPERATIONAL DEFINTIONS
ACTIVITY
• Determine an operational definition for
each underlined variable.
• Remember an operational definition is
observable and measurable.
24
Operational Definitions:
•The teacher wants to find a way to help make Billy act more friendly toward
other children.
•A psychologist wants to know if the new form of psychotherapy will make
people less depressed.
•A student wants to find a way to study more efficiently.
•Does this drug help people overcome tiredness?
•Boys show more affection for their fathers than their mothers.
•People dream more if they have a big meal before going to sleep.
•College athletes are not as smart as regular students.
•Overall senior girls are prettier than sophomore girls.
•How does grade point average affect a person’s sense of humor?
•People who make over $100,000 a year tend to be snobs.
25
TO TEST A HYPOTHESIS
•
•
•
•
•
Make an observation
Describe the behavior
Detect correlations that predict the
behavior
Design research
Develop a hypothesis about North Penn
student behavior. The hypothesis should
have variables that can be operationally
26
defined.
HYPOTHESIS
• Replication is the main goal of all good
research.
• Replication allows researchers to test
hypotheses with other samples from other
populations so that results can be
generalized.
27
Description: Starting point of any
science.
Case Study
A technique in which one person, group, or
situation is studied in depth to reveal underlying
behavioral principles.
Susan Kuklin/ Photo Researchers
Is language uniquely human?
28
CASE STUDY
• Long tradition in clinical work, Freud’s
theory of psychoanalysis
• Can include tests, interviews, analysis of
letters, or transcripts
29
CASE STUDY
• EXAMPLES: Freud, Piaget, chimp
studies, Phineas Gage
• Advantages:
– Depth of information
– Appropriate for new, rare, or complex cases,
• Disadvantages:
– Individual may be atypical or unrepresentative
– Anecdotal information can overwhelm general
truths
30
Case Study
Clinical Study
http://behavioralhealth.typepad.com
A clinical study is a form of
case study in which the
therapist investigates the
problems associated with a
client. Example: Oliver
Sack’s “The Man Who
Mistook His Wife for his Hat”
31
Survey
A technique for ascertaining the self-reported
attitudes, opinions or behaviors of people
usually done by questioning a representative,
random sample of people.
http://www.lynnefeatherstone.org
32
TROUBLESHOOTING:
• A random sample typically generates a
representative sample.
• Random assignment involves taking a
randomly chosen sample and assigning
the participants at random to either the
experimental or control group of an
experiment. (only used in experiments)
33
SURVEY
• Use interviews or questionnaires to ask
about behavior, attitudes, opinions, beliefs,
or intentions
34
Survey
Wording Effect
Wording can change the results of a survey and
thus affect validity.
Q: Should cigarette ads and pornography be
allowed on television? (not allowed vs. forbid)
35
WORDING EFFECTS
• The Statistical Assessment Service
nominated the following 1937 British
Gallup Poll question as a leading
candidate for the “Worst Poll Question of
All Time”.
• “Are you in favor of direct retaliatory
measures against Franco’s piracy?”
• Why? Modern example?
36
PROBLEMS WITH QUESTION
1.
2.
3.
4.
5.
It is not balanced.
It assumes knowledge
It does not use everyday language.
It employs a perjorative.
It is vague
37
WORDING EFFECTS
• Women with young children should be
able to work outside the home.
– 8 in 10 Americans agreed
38
WORDING EFFECTS
• Women should stay at home if they have
young preschool children.
• 7 in 10 Americans agreed
39
WORDING EFFECTS
• The problems faced by blacks have been
brought on by blacks themselves
40
• With a white interviewer: 62% of whites
agreed
• With a black interviewer: 46% of whites
agreed
41
SURVEY
• People may be reluctant to admit
undesirable or embarrassing things about
themselves.
• Or they may say what they think they
should say..
• Examples
42
WORDING EFFECTS
• Not allowing vs forbidding
• More restrictions vs government
censorship
• Aid to needy vs welfare
• Affirmative action vs preferential treatment
43
Survey
False Consensus Effect
A tendency to overestimate the extent to which
others share our beliefs and behaviors.
Example?
44
Survey
Random Sampling
If each member of a
population has an equal
chance of inclusion into a
sample, it is called a random
sample (unbiased). If the
survey sample is biased, its
results are not valid. Only
those who want to make a
point may respond
The fastest way to know about the
marble color ratio is to blindly
transfer a few into a smaller jar and
count them.
45
Random Sampling Exercise
• Various Scenarios
• Basketbally Activity
46
ACTIVITY
• Get out of your seats. Push the seats
back. You may not sit down or lean
against anything.
47
Naturalistic Observation
Examples: Observing and recording the behavior
of animals in the wild; recording self-seating
patterns in a multiracial school lunch room.
Courtesy of Gilda Morelli
48
NATURALISTIC OBSERVATION
• Describes, does not explain
• Often used by ethologists such as Jane
Goodall
• Behavior changes when you know you are
being watched
• Observations may be distorted by what the
experimenters expect to see.
• Other advantages, disadvantages?
49
Descriptive Methods
Summary
Case studies, surveys, and naturalistic
observation describe behaviors.
50
CORRELATION
• Correlation = relationship between
variables
• Variables = the specific factors or
characteristics that are manipulated and
measured in research
• Evidence should be evaluated in terms of
reliability and validity
• Reliability: repeatable (replication)
• Validity: accurately assesses topic
51
CORRELATION
• Scatterplots: represent the values of two
variables; indicates correlation or
relationship between the variables
• Measured by the correlation coefficient, a
statistical measure of relationship. The
extent to which two factors vary together,
and thus of how well either factor predicts
the other.
52
Scatterplots
Perfect positive
correlation (+1.00)
Scatterplot is a graph comprised of points that are
generated by values of two variables. The slope of
the points depicts the direction, while the amount
of scatter depicts the strength of the relationship.
53
Scatterplots
Perfect negative
correlation (-1.00)
No relationship (0.00)
The Scatterplot on the left shows a negative correlation,
while the one on the right shows no relationship between
the two variables.
54
Data
Data showing height and temperament in people.
55
Scatterplot
The Scatterplot below shows the relationship
between height and temperament in people. There
is a moderate positive correlation of +0.63.
56
CORRELATION
• POSITIVE CORRELATION: A direct
relationship. Two variables increase or
decrease together.
• NEGATIVE CORRELATION: An inverse
relationship. As one variable increases,
the other decreases.
57
Correlation
When one trait or behavior accompanies
another, we say the two correlate.
Indicates strength
of relationship
(0.00 to 1.00)
Correlation
coefficient
Correlation Coefficient is a
statistical measure of the
relationship between two
variables.
r = + 0.37
Indicates direction
of relationship
(positive or negative)
58
CORRELATION
• Strength of the relationship is indicated by
the number.
– The closer it is to zero, the weaker the
relationship
– The closer it is to one (plus or minus), the
stronger the relationship
– Interpret:
• +.8, -,2, -.9, +.3
59
Correlation does not mean
causation!!!
or
60
Illusory Correlation
The perception of a relationship where no
relationship actually exists. When we believe there is
a relationship we are likely to notice and recall
instances that confirm our belief: Parents conceive
children after adoption.
Adopt
Confirming
evidence
Disconfirming
evidence
Do not
adopt
Disconfirming
evidence
Confirming
evidence
Michael Newman Jr./ Photo Edit
Conceive
Do not
conceive
61
ILLUSORY CORRELATIONS
• Examples of Illusory Correlations:
It always rains when …
The phone always rings when…
More serious implications?
62
Illusory Correlation
The Point to Remember:
Michael Newman Jr./ Photo Edit
When we notice random coincidences, we may
forget that they are random and instead see
them as correlated. Thus we can easily deceive
ourselves by seeing what is not there.
63
Correlation
•The Point To Remember:
•A correlation coefficient helps us see the
world more clearly by revealing the
extent to which two things relate.
64
Correlation and Causation
• Very important to remember:
Correlation does necessarily
prove causation!
65
Order in Random Events
Given random data, we look for order and
meaningful patterns.
Your chances of being dealt either of these hands is
precisely the same: 1 in 2,598,960.
66
Order in Random Events
Given large numbers of random outcomes, a few
are likely to express order.
Jerry Telfer/ San Francisco Chronicle
Angelo and Maria Gallina won two
California lottery games on the same day.
67
Reaction Time Activity
68
Experimentation
Exploring Cause and Effect
Like other sciences, experimentation is the
backbone of psychology research. Experiments
isolate causes and their effects.
69
Exploring Cause & Effect
Many factors influence our behavior. Experiments
(1) manipulate factors that interest us, while other
factors are kept under (2) control.
Effects generated by manipulated factors isolate
cause and effect relationships.
70
Independent Variable
An Independent Variable is a factor manipulated
by the experimenter. The effect of the independent
variable is the focus of the study.
For example, when examining the effects of breast
feeding upon intelligence, breast feeding is the
independent variable.
71
Dependent Variable
A Dependent Variable is a factor that may change
in response to an independent variable. In
psychology, it is usually a behavior or a mental
process.
For example, in our study on the effect of breast
feeding upon intelligence, intelligence is the
dependent variable.
72
IV/DV Activity
• Identify the Independent/Dependent
Variable.
73
EXPERIMENT
• Experimenters aim to manipulate an
independent variable, measure the
dependent variable, and control all other
variables.
• When determining i.v. and d.v., think “what
(IV) affects what (DV)?””
• Practice exercises
• Reaction time experiment
74
CONTROLING OTHER
VARIABLES
• An experiment has at least two different
conditions:
• control condition
• experimental condition
• Random assignment of subjects between
conditions equates the conditions.
Basketball example.
75
EXPERIMENTAL DESIGN
Representative
Sample (larger
the better)
Experimental
Group
Independent
Variable
Measure
Dependent
Variable
Random
Assignment
Control
Group
=
Placebo
Is the difference
statistically
significant?
Measure
Dependent
Variable
Apply Methods of
Control
Apply Methods of
Control
Population
76
CONFOUNDING AND RANDOM
VARIABLES
• Types of Confounding Variables:
– Random Variables
– Participants Expectations
– Experimenter Bias
• These variables need to be eliminated when
possible. Why?
• Random assignment is presumed to distribute
impact of uncontrolled variables randomly and
probably equally across groups.
77
OTHER METHODS OF CONTROL
• Eliminating confirmation bias
• Eliminating order effects
• Matching conditions to eliminate
confounding variables
• Double blind
• Eliminate experimenter bias
78
Experimentation
A summary of steps during experimentation.
79
EXPERIMENTATION
• Population (group you are generalizing
your hypothesis to)
• Random sample from the population
• Random sample creates a representative
sample rather than a biased sample
• Random assignment of subjects to
experimental group or control group
80
EXPERIMENTATION
• Experimental group gets the independent
variable
• Control group gets the placebo
• Be sure all measures of control are in
place so the only thing influencing the
results (dependent variable) is the
independent variable
81
EXPERIMENTATION
• Measure the dependent variable (you can do
this because of operational definitions)
• Compare the results between the experimental
group and the control group using inferential
statistics.
• Is there a statistically significant difference?
– This means that the difference we observed is
probably not due to chance variation between the
samples.
– Do not make much of a finding unless the odds of
its occurring by chance are less than 5% (.05).
• If so, you have established a causal
relationship.
82
Statistical Significance
• Criterion is usually 5% (0.05) or 1 in 20
• Statistical significance indicates the likelihood
that a result will happen by chance; it does not
indicate importance of result.
83
Comparison
Below is a comparison of different research
methods.
84
EXPERIMENTAL DESIGN
Representative
Sample (larger
the better)
Experimental
Group
Independent
Variable
Measure
Dependent
Variable
Random
Assignment
Control
Group
=
Placebo
Is the difference
statistically
significant?
Measure
Dependent
Variable
Apply Methods of
Control
Apply Methods of
Control
Population
85
ETHICAL PRINCIPLES
• Established by the American
Psychological Association
– Obtain informed consent of potential
participants
– Protect subjects from harm and discomfort
– Treat information about subjects confidentially
– Fully explain the research afterward (debrief)
– Institutional Review Boards (IRB) should
screen research proposals
86
STATISTICS
• Statistics will be taught in a future chapter
• For now:
– Correlation coefficient
– Representative samples are better than
biased samples
– Less variable cases are better than more
variable
– Statistical significance: difference is probably
not due to chance variation between sample
(less than .05)
87
ESSAY WRITING
• Never use bullets, sentence fragments,
etc. Full sentences, essay format
required.
• You do not need to restate the question
unless this clarifies your thinking.
• Underline key terms especially verbs in
the question
88
ESSAY WRITING
• Get to the point, introductions and
conclusions are not necessary
• Address each part of the question
• Define all terms and give an application or
example whenever possible.
• Underline all terms.
• Keep your audience in mind.
89
Practice Outlining Essay
• Research Methods
90
STATISTICS
Totally independent: Study Guide; quiet time on
your choice of work
Need some work on the details: Listen to Mrs. S;
work with a partner on Study Guide
No background: Listen to Mrs. S; work with Mrs. S
Study Guide Tests begin on p. 457
91
Statistical Reasoning
Statistical procedures analyze and interpret data
allowing us to see what the unaided eye misses.
Composition of ethnicity in urban locales
92
Measures of Central Tendency
Mode: The most frequently occurring score
in a distribution.
Mean: The arithmetic average of scores in a
distribution obtained by adding the
scores and then dividing by the number
of scores that were added together.
Median: The middle score in a rank-ordered
distribution.
93
Measures of Central Tendency
A Skewed Distribution
94
Measures of Variation
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.
95
Standard Deviation
96
Making Inferences
A statistical statement of how frequently an
obtained result occurred by experimental
manipulation or by chance.
97
Making Inferences
When is an Observed Difference Reliable?
1. Representative samples are better than biased
samples.
2. Less variable observations are more reliable
than more variable ones.
3. More cases are better than fewer cases.
98
Making Inferences
When is a Difference Significant?
When sample averages are reliable and the
difference between them is relatively large, we say
the difference has statistical significance.
For psychologists this difference is measured
through alpha level set at 5 percent.
99
FAQ
Q1. Can laboratory experiments illuminate
everyday life?
Ans: Artificial laboratory conditions are created to
study behavior in simplistic terms. The goal is to
find underlying principles that govern behavior.
100
FAQ
Q2. Does behavior depend on one’s culture?
Ans: Even when specific attitudes and behaviors
vary across cultures, as they often do, the
underlying processes are much the same.
Ami Vitale/ Getty Images
101
FAQ
Q3. Does behavior vary with gender?
Ans: Yes. Biology determines our sex, and culture
further bends the genders. However, in many
ways woman and man are similarly human.
102
FAQ
Q4. Why do psychologists study animals?
Ans: Studying animals gives us the understanding
of many behaviors that may have common biology
across animals and humans.
D. Shapiro, © Wildlife Conservation Society
103
FAQ
Q5. Is it ethical to experiment on animals?
Ans: Yes. To gain insights to devastating and fatal
diseases. All researchers who deal with animal
research are required to follow ethical guidelines
in caring for these animals.
104
FAQ
Q6. Is it ethical to experiment on people?
Ans: Yes. Experiments that do not involve any
kind of physical or psychological harm beyond
normal levels encountered in daily life may be
carried out.
105
FAQ
Q7. Is psychology free of value judgments?
Ans: No. Psychology emerges from people who
subscribe to a set of values and judgments.
106
© Roger Shepard
FAQ
Q8. Is psychology potentially dangerous?
Ans: It can be, but it is not. The purpose of
psychology is to help humanity with problems
such as war, hunger, prejudice, crime, family
dysfunction, etc.
107