Henderson State University
Worth Publishers, © 2006 1
Thinking Critically with
The Need for Psychological Science
Intuition & Common Sense
Many people believe that intuition and common
sense are enough to bring forth answers regarding
Intuition and common sense may aid queries,
but they are not free of error.
Limits of Human Intuition
Limits of Intuition
Personal interviewers may
rely too much on their “gut
feelings” when meeting
with job applicants.
Taxi/ Getty Images
Hindsight Bias is the “I-knew-it-all-along”
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.
• I feel 98 percent certain that the area of the U.S. is
more than ____ square miles but less than ____
• 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 ___.
• 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
Sometimes we think we
know more than we
How long do you think it
would take to unscramble WREAT WATER
People said it would take
about 10 seconds, yet on
average they took about 3
minutes (Goranson, 1978).
Now try this word scramble! Anagram
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
1. How can we differentiate between
uniformed opinions and examined
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!
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).
Critical thinking does
not accept arguments
Courtesy of the James Randi Education Foundation
and conclusions blindly.
evaluates evidence and
The Amazing Randi
Psychologists, like all scientists, use the
scientific method to construct theories that
organize, summarize and simplify
A Theory is an explanation that integrates
principles and organizes and predicts
behavior or events.
For example, low self-esteem contributes to
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
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.
• To reduce bias psychologists report their
research with operational definitions.
• An operational definition states how the
variable is observed and measured.
• Operational definitions allows others to
replicate (repeat) the observations.
• Determine an operational definition for
each underlined variable.
• Remember an operational definition is
observable and measurable.
TO TEST A HYPOTHESIS
• Make an observation
• Describe the behavior
• Detect correlations that predict the
• Design research
• Develop a hypothesis about North Penn
Description: Starting point of any
A technique in which one person, group, or
situation is studied in depth to reveal underlying
Susan Kuklin/ Photo Researchers
Is language uniquely human? 24
• Long tradition in clinical work, Freud’s
theory of psychoanalysis
• Can include tests, interviews, analysis of
letters, or transcripts
• EXAMPLES: Freud, Piaget, chimp
studies, Phineas Gage
– Depth of information
– Appropriate for new, rare, or complex cases,
– Individual may be atypical or unrepresentative
– Anecdotal information can overwhelm general
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”
A technique for ascertaining the self-reported
attitudes, opinions or behaviors of people
usually done by questioning a representative,
random sample of people.
• Use interviews or questionnaires to ask
about behavior, attitudes, opinions, beliefs,
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)
• The Statistical Assessment Service
nominated the following 1937 British
Gallup Poll question as a leading
candidate for the “Worst Poll Question of
• “Are you in favor of direct retaliatory
measures against Franco’s piracy?”
• Why? Modern example?
PROBLEMS WITH QUESTION
1. It is not balanced.
2. It assumes knowledge
3. It does not use everyday language.
4. It employs a perjorative.
5. It is vague
• Women with young children should be
able to work outside the home.
– 8 in 10 Americans agreed
• Women should stay at home if they have
young preschool children.
• 7 in 10 Americans agreed
• The problems faced by blacks have been
brought on by blacks themselves
• With a white interviewer: 62% of whites
• With a black interviewer: 46% of whites
• Not allowing vs forbidding
• More restrictions vs government
• Aid to needy vs welfare
• Affirmative action vs preferential treatment
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. 38
Random Sampling Exercise
• Various Scenarios
• Basketbally Activity
• People may be reluctant to admit
undesirable or embarrassing things about
• Or they may say what they think they
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
• Describes, does not explain
• Often used by ethologists such as Jane
• Behavior changes when you know you are
• Observations may be distorted by what the
experimenters expect to see.
• Other advantages, disadvantages?
Case studies, surveys, and naturalistic
observation describe behaviors.
• Correlation = relationship between
• 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
• 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
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.
Perfect negative 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.
Data showing height and temperament in people.
The Scatterplot below shows the relationship
between height and temperament in people. There
is a moderate positive correlation of +0.63.
• POSITIVE CORRELATION: A direct
relationship. Two variables increase or
• NEGATIVE CORRELATION: An inverse
relationship. As one variable increases,
the other decreases.
When one trait or behavior accompanies
another, we say the two correlate.
(0.00 to 1.00)
coefficient r = + 0.37
Correlation Coefficient is a
statistical measure of the Indicates direction
relationship between two of relationship
variables. (positive or negative) 51
• Strength of the relationship is indicated by
– The closer it is to zero, the weaker the
– The closer it is to one (plus or minus), the
stronger the relationship
• +.8, -,2, -.9, +.3
Correlation does not mean
• Bald Men/Marriage
• High School Students/Attitude
•The Point To Remember:
•A correlation coefficient helps us see the
world more clearly by revealing the
extent to which two things relate.
Correlation and Causation
• Very important to remember:
Correlation does necessarily
Reaction Time Activity
Exploring Cause and Effect
Like other sciences, experimentation is the
backbone of psychology research. Experiments
isolate causes and their effects.
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.
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
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
For example, in our study on the effect of breast
feeding upon intelligence, intelligence is the
• Identify the Independent/Dependent
• An experiment has at least two different
• control condition
• experimental condition
• Random assignment of subjects between
conditions equates the conditions.
CONFOUNDING AND RANDOM
• Types of Confounding Variables:
– Random Variables
– Participants Expectations
– Experimenter Bias
• Random assignment is presumed to distribute
impact of uncontrolled variables randomly and
probably equally across groups.
OTHER METHODS OF CONTROL
• Eliminating confirmation bias
• Eliminating order effects
• Matching conditions to eliminate
• Double blind
• Eliminate experimenter bias
– Experimenter expectancies (maze bright)
– Confirmation bias
A summary of steps during experimentation.
Below is a comparison of different research
• Established by the American
– Obtain informed consent of potential
– 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
A statistical statement of how frequently an
obtained result occurred by experimental
manipulation or by chance.
When is an Observed Difference Reliable?
1. Representative samples are better than biased
2. Less variable observations are more reliable
than more variable ones.
3. More cases are better than fewer cases.
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.
Q1. Can laboratory experiments illuminate
Ans: Artificial laboratory conditions are created to
study behavior in simplistic terms. The goal is to
find underlying principles that govern behavior.
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
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.
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
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.
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
Q7. Is psychology free of value judgments?
Ans: No. Psychology emerges from people who
subscribe to a set of values and judgments.
© Roger Shepard
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