Impression of Psychology
With hopes of satisfying curiosity, many people
listen to talk-radio counselors and psychics to
learn about others and themselves.
Dr. Crane (radio-shrink)
Psychic (Ball gazing)
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.
Limits of Intuition
Personal interviewers may
rely too much on their “gut
feelings” when meeting with
job applicants.
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.
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
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!
The Need for
Psychological Science
The biases and errors of people’s everyday
judgments illustrate the need for:
1. Skepticism
2. Humility
3. Critical Thinking
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
Goals of Psychology
Describe
 Explain
 Predict
 Control

behavior and mental
processes
Scientific Method

Formulate testable questions
 Develop

hypotheses
Design study to collect data
 Experimental
 Descriptive

Analyze data to arrive at conclusions
 Use
of statistical procedures
 Use of meta-analysis

Report results
 Publication
 Replication
The Need for
Psychological Science
 Theory
 an explanation using an integrated set of
principles that organizes and predicts
observations
 For example, low self-esteem contributes to depression.
 Hypothesis
 a testable prediction
 often implied by a theory
 People with low self-esteem are apt to feel more
depressed.
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.
The Need for
Psychological Science
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
 Testing the effects of vitamin C on the health
of students could be measured by the number
of colds experienced during the month.
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
Thinking Critically …
Description
 The Case Study
 The Survey
 Naturalistic Observation
Thinking Critically …
Correlation
 Correlation and Causation
 Illusory Correlation
 Perceiving Order in Random
Events
Thinking Critically …
Experimentation
 Exploring Cause and Effect
 Evaluating Therapies
 Independent and Dependent
Variables
Description
Psychologists describe behavior
using case studies, surveys,
and naturalistic observation
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?
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.
The Case Study Method
Defined as a thorough, exhaustive study of a person.
It includes personal, educational, family and work
histories.
Advantage:
A wealth of background information about
one person
Disadvantages:
Information cannot be generalized to others;
also, researcher’s biases can influence
subject’s behavior.
Description
 Survey
 technique for ascertaining the self-reported
attitudes or behaviors of people
 usually by questioning a representative, random
sample of people
Survey
Wording Effect
Wording can change the results of a survey.
 Even subtle changes in the order or wording of
questions can have major effects.
Q: Should cigarette ads and pornography be
allowed on television? (not allowed vs. forbid)
The Survey Method
Defined as asking questions of a carefully selected
group of people and tabulating their answers.
Advantage:
Information can be gathered about
feelings, opinions, and behavior
patterns.
Disadvantages:
Interpretation difficult; people lie;
sample may not be representative.
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
Samples and Sampling
Sample
selected segment of the population
Representative sample
closely parallels the population on relevant
characteristics
Random selection
every member of larger group has equal
change of being selected for the study
sample
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.
The fastest way to know about the
marble color ratio is to blindly
transfer a few into a smaller jar and
count them.
Description
 Naturalistic
Observation
 observing and
recording behavior
in naturally
occurring situations
without trying to
manipulate and
control the situation
Naturalistic Observation
Observing and recording the behavior of animals in the wild
and recording self-seating patterns in a multiracial school
lunch room constitute naturalistic observation.
Courtesy of Gilda Morelli
The Naturalistic
Observation Method
Defined as observing behaviors in their
natural settings.
Disadvantages:
Researcher cannot interact with the
subject.
Researcher may interpret subject’s
responses incorrectly.
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)
Coefficient of Correlation
Numerical indication of magnitude and
direction of the relationship between
two variables
Positive correlation— two variables
vary systematically in the SAME direction
Negative correlation— two variables
vary systematically in OPPOSITE directions
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.
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.
Data
Data showing height and temperament in people.
Scatterplot
The Scatterplot below shows the relationship
between height and temperament in people. There
is a moderate positive correlation of +0.63.
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
Illusory Correlation
The perception of a relationship where no relationship
actually exists. 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
Two Random Sequences
 Your chances of
being dealt
either of these
hands is
precisely the
same: 1 in
2,598,960.
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.
Experimentation
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.
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
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
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
Experimental Design
Random sample— every member of the
population being studied should have an equal
chance of being selected for the study
Random assignment— assigning subjects
to experimental and control conditions by chance.
Randomization helps avoid false results
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
Conducting
Psychology
Experiments
Hypothesis
• Scientific method
• Hypothesis
formulation
=
Operationalization
• Operationalization: to put an experiment into a form
that allows researchers to test the hypothesis
• Independent variable: the variable that researchers
control
• Dependent variable: the variable that researchers are
studying
• What other questions should the researchers ask?
Independent
variable
Dependent
variable
Operationalization
• Confounding
variables
• Reliability
• Validity
SCARY
= ?
What makes a
movie scary?
What else might
cause nightmares?
How can we tell if
a child has had a
nightmare?
Experimenting, Recording
Results, Conclusion
Conducting the experiment
Recording the results
Drawing conclusions
does cause
Correlation vs. Causation
Correlation versus causation: just because two things
are related doesn’t mean one thing caused the other
Just because
happened
and then
doesn’t necessarily mean that
caused
happened
Replication and Theory
Development
• Replication
• Theory
development
Experiment 1
results
Experiment 2
results
Experiment 3
results
THEORY:
=
=
=
=
Hypothesis
Independent Variable
Groups
Dependent Variable
X amount of sleeping pills helps the healthy
person with insomnia to sleep better.
Sleeping pills
Placebos
Experimental
Group
Control
Group
# of people who
had restful nights
# of people who
had restful nights
The hypothesis proves to be incorrect. People taking the sleeping
pill over a period of days had more insomnia than before. They
had less restful sleep than the people in the control group.
Basic Ethical Guidelines for
Psychological Researchers
Do no harm.
Accurately describe risks to potential subjects.
Ensure that participation is voluntary.
Minimize any discomfort to participants.
Maintain confidentiality.
Do not unnecessarily invade privacy.
Remove any misconceptions caused by deception
(debrief).
Provide results and interpretations to participants.
Treat participants with dignity and respect.
Evaluating Media Reports
• Be skeptical of sensationalist claims
• Goal of “shock” media is ratings
• Look for original sources
• Separate opinion from data
• Consider methodology and operational
definitions
• Correlation is not causality
• Skepticism is the rule in science.
Experimentation
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.
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
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.
Ethical Issues
 Is it right to experiment
on animals?
 What limits should there
be?
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
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.
Ethical Issues
 Is it right to experiment on
people?
 What limits should there be?
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.
FAQ
Q7. Is psychology free of value judgments?
Ans: No. Psychology emerges from people who
subscribe to a set of values and judgments.
© 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.
Statistical Reasoning
Statistical procedures analyze and interpret data
allowing us to see what the unaided eye misses.
Composition of ethnicity in urban locales
Frequency Distribution
Frequency Distributions
• 1. What are they?
– Tables
– Graphs
• Bar
• Histogram
Distributions
Percentile Rank--the percentage of
scores that fall below a particular score.
You can never have a percentile rank of
100 because you are part of that 100.
(You can’t exceed yourself!)
Bar Graphs (histograms)-Percentile ranks and distributions can be
represented in bar graphs or histograms.
Histogram
Statistical Reasoning
Percentage
still functioning
after 10 years
100%
99
98
97
96
95
Our Brand Brand Brand
Brand
X
Y
Z
Brand of truck
Statistical Reasoning
Percentage
still functioning
after 10 years
100%
90
80
70
60
50
40
30
20
10
0
Our Brand
Brand
X
Brand Brand
Y
Z
Brand of truck
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
Median
 Separates the upper and low half of
distribution
1) mean and median not necessarily equal
2) median much less sensitive to extremes
Mode
•
•
•
•
•
Most common value
Always present in the distribution
May be more than one mode
Used mainly with nominal data
Plays minor role in statistical inference
Statistical Reasoning
A Positively Skewed Distribution
15 20 25 30 35 40 45 50
90
475
70
Mode Median
One Family
Mean
Income per family in thousands of dollars
710
Skewed Distributions
Positive
Mean > Median
Negative
Mean < Median
Measures of Variation
 Range
 the difference between the highest and lowest
scores in a distribution
Measures of Variation
Standard Deviation: A computed measure of how
much scores vary around the mean.
Table 1.4
Myers: Psychology, Eighth Edition
Copyright © 2007 by Worth Publishers
Variation
Normal Curve--a bell-shaped curve that
describes the normal distribution of many
types of data. Most scores fall near the
mean and fewer and fewer fall near the
extremes. In a normal curve the mean,
median and mode are all near the middle.
Making Inferences
A statistical statement of how frequently an
obtained result occurred by experimental
manipulation or by chance.
Correlation
Regression toward the mean— falling
back to the norm. It can fuel the illusion
that uncontrollable events correlate with
out actions.
Statistical Inference
When is it safe to generalize from a sample?
1. Representative Samples are better than biased
samples.
2. Less-variable observations are more reliable
than those that are more variable.
3. More cases are better than fewer. Larger
samples are better than smaller ones.
4. As the size of a sample increases, the size of the
standard deviation is most likely to decrease
When is a difference significant?
When sample averages are reliable and
the difference between them is large we
say the difference has statistical
significance (it reflects a real difference
not due to chance or variation between
samples).
For psychologists this difference is
measured through alpha level set at 5
percent.