 Thinking Critically With Psychology
 Thinking Critically With Psychology
The Need for Psychological Science
 Thinking Critically With Psychology
The Need for Psychological Science
Did We Know It All Along?
After the first two murders
at Virginia Tech, and before
the massacre, many
people say it was obvious
that the university should
have locked down campus.
Commonsense describes
what has happened after
the fact more easily than it
predicts what will happen
before the fact. This is
called the hindsight bias.
Hindsight is 20/20!
A thought experiment: Tell one group of people that
“psychologists have found that separation weakens
romantic attraction.” Asked to imagine why this is true, what
do you suppose people will say?
I already knew that!
Commonsense! Out of
sight, out of mind!
A thought experiment: Tell one group of people that
“psychologists have found that separation weakens
romantic attraction.” Asked to imagine why this is true, what
do you suppose people will say?
A thought experiment: Tell another group of people that
“psychologists have found that separation strengthens
romantic attraction.” Asked to imagine why this is true, what
will do you suppose people will say?
I already knew that!
Commonsense! Absence
makes the heart grow
fonder!
A thought experiment: Tell another group of people that
“psychologists have found that separation strengthens
romantic attraction.” Asked to imagine why this is true, what
will do you suppose people will say?
 Thinking Critically With Psychology
The Need for Psychological Science
Psychology Makes the World a
Better Place to Live
The innovation: the limegreen fire truck.
The rationale: perceptual
psychologists’ discovery
that the human visual
system is most sensitive to
light with wave lengths
between 510 and 570 nm.
400 nm
500 nm
600 nm
700 nm
Accidents Per 100,000 Runs
14
12
10
8
6
4
2
0
The result: lime-green
fire trucks are more than
three times less likely to be
in a traffic accident than
red fire trucks (Solomon &
King, 1995).
The innovation: the
sequential police lineup
procedure, in which a
witness is shown suspects
one at a time instead of all
at once (simultaneously).
The rationale:
psychologist Gary Wells’
discovery that when shown
sequential lineups, people
make absolute judgments,
which lead to much lower
rates of misidentification.
The result: sequential
lineups cut eyewitness
misidentification in half
compared to simultaneous
lineups. Fewer innocent
people go to jail.
 Thinking Critically with Psychology
How Do Psychologists Ask and
Answer Questions?
The Scientific Method
Theory
Hypothesis
Theory – an explanation
using an integrated set of
principles that organizes
observations.
Theory
Hypothesis
Hypothesis – a testable
prediction implied by a
theory.
We might theorize that
the cause of depression
is low self-esteem—one’s
feelings of self-worth.
We might hypothesize
that depression and selfesteem will correlate
negatively.
We might test this
hypothesis by seeing if
people who receive a low
score for self-esteem
tend to receive a high
score for depression.
Research Process
 Thinking Critically with Psychology
How Do Psychologists Ask and
Answer Questions?
Generating a research question
Generating a Research Question
Everyday observation –
One source of research
questions psychology is
simply observing the
world around you and
asking questions about
why people think and
behave as they do.
Generating a Research Question
In the 1960s, social
psychologists John Darley
and Bibb Latane were
horrified by the brutal
murder of a woman named
Kitty Genovese. It was
widely reported that
dozens of neighbors
witnessed or were aware
of the attack—but no one
helped.
Generating a Research Question
Generating a Research Question
Darley and Latane
hypothesized that any
given bystander is less
likely to give aid to a victim
if other bystanders are
present. In a series of
studies, Darley and Latane
found that this is indeed
the case.
http://www.youtube.com/watch_popup?v=JcowGVd6GqY&vq=medium
Generating a Research Question
Generating a Research Question
Generating a Research Question
Generating a Research Question
Personal experience –
Like you, psychologists
want to understand their
own tendencies, and
foibles.
http://www.nytimes.com/2014/07/15/science/which-matters-more-talent-or-practice.html?_r=0
Generating a Research Question
Replication – seeing
whether a basic finding
can be observed again
with different participants
and under different
circumstances.
Generating a Research Question
After the original study of
the bystander effect, there
were dozens of follow-up
studies aimed at answering
specific questions about
the effect.
 Thinking Critically with Psychology
How Do Psychologists Ask and
Answer Questions?
Establishing operational
definitions
Establishing Operational Definitions
Operational definition –
a specific statement of the
procedures used to define
research variables, so as
to allow others to replicate
the original observations.
Establishing Operational Definitions
An operational definition of
intelligence might be the
number correct on tests of
verbal, spatial, numerical,
and reasoning abilities.
 Thinking Critically with Psychology
How Do Psychologists Ask and
Answer Questions?
Choosing a research design
Choosing a Research Design
Setting
Three major types of research
designs that psychologists use
in their research…
Lab
Descriptive
Methods
Correlational
Experimental
Field
 Thinking Critically With Psychology
Descriptive Methods
The Case Study – an in depth
investigation of a single (or very
few) subjects
The Case Study
Through a 30-year case
study, Irene Pepperberg
concluded that African
Grey parrot Alex could
name and categorize
objects, and comprehend
numbers up to six.
http://www.youtube.com/watch?v=7yGOgs_UlEc
The Case Study
Through a series of
case studies, often of
his own children, Jean
Piaget developed an
influential theory of
cognitive development,
which assumes that
cognitive functions
unfold through a series
of distinct stages.
The Case Study
http://www.youtube.com/watch_popup?v=ue8y-JVhjS0&vq=small
 Thinking Critically With Psychology
Descriptive Methods
The Survey – an investigation of
many cases in less depth by
asking people to report opinions
and behaviors
The Survey
A technique for ascertaining the self-reported attitudes,
opinions or behaviors of people usually done by
questioning a representative sample of people—one that
accurately portrays the population of interest.
The Survey
 Thinking Critically With Psychology
Descriptive Methods
Naturalistic Observation –
recording behavior in its natural
environments, and describing it in
detail
Naturalistic Observation
Credit: Delphine Bruyere
Primatologist Jane
Goodall used naturalistic
observation to study
chimpanzees. She
concluded, “Observations,
made in the natural
habitat, helped to show
that the societies and
behavior of animals are far
more complex than
previously supposed.”
Naturalistic Observation
Psychologists have used
naturalistic observation to
study, effects of social
interaction on people’s
behavior. One study
found that people laugh
30 times more often in
social situations than in
solitary situations
(Provine, 2001).
 Thinking Critically With Psychology
Experimental Methods
Purpose is to explore cause and
effect by manipulating one or
more factors, while holding other
factors constant
Independent and Dependent Variables
Variable – anything that
can fluctuate. Whether
it’s rainy or sunny, warm
or cold, or whether a
person is male or
female, or in a good
mood or a bad mood,
are all examples.
Independent and Dependent Variables
Independent variable –
aspect of the situation
or of individuals that
can vary independently
of other variables. The
variables whose effect
is being studied.
Online vs. Classroom
Independent and Dependent Variables
Dependent variable –
the variable that may
change in response to
manipulations of the
independent variable.
Score on Test
Independent and Dependent Variables
An Example: Does
breastfeeding children
have an impact on their
intelligence later in life?
Independent and Dependent Variables
The independent variable is whether mothers are
assigned to an experimental condition in which their
children breast feed, or to a control condition in which they
feed their children formula.
Independent and Dependent Variables
The dependent variable is the child’s score on an
intelligence test at age 8. (This is the measureable aspect
of psychological functioning that we think may be
influenced by the independent variable.)
Random Assignment
Random assignment – assigning participants to
experimental and control groups by chance, thus
minimizing preexisting differences between the groups that
could affect the dependent variable (e.g., SES).
Cause
Effect
http://www.youtube.com/watch_popup?v=hHHdovKHDNU&vq=medium
Sometimes it’s not
possible to conduct an
experiment. For example,
it isn’t possible to assign a
child to be male or female
for the purpose of an
experiment.
Other times, it’s unethical
to conduct an experiment.
For example, it would be
unethical to assign people
to be exposed to polluted
air or non-polluted air for
the purpose of seeing
whether pollution has a
negative effect on mental
functioning.
 Thinking Critically with Psychology
Correlational Methods
Purpose is to observe naturally
occurring relationships between
variables
 Thinking Critically with Psychology
Correlational Methods
Correlation coefficient – a statistical
index (-1 to 1) of the relationship
between two variables
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, while the
amount of scatter suggests the strength of the relationship.
Test Score
Time Spent Studying
Correlation and Causation
We might theorize that
the cause of depression
is low self-esteem—one’s
feelings of self-worth.
Correlation and Causation
We might hypothesize
that depression and selfesteem will correlate
negatively.
Correlation and Causation
We might test this
hypothesis by seeing if
people who receive a low
score for self-esteem
tend to receive a high
score for depression.
Correlation and Causation
30
Depression
25
20
15
10
5
0
0
5
10
15
Self Esteem
20
25
30
Correlation and Causation
or
Correlation and Causation
Correlation does not mean causation!
or
Correlation and Causation
or
Correlation and Causation
or
 Thinking Critically with Psychology
Research Ethics
Is it Ethical to Experiment on
People?
The Milgram Experiments
The Milgram Experiments
Was it that Eichmann and his
accomplices in the Holocaust had
mutual intent, in at least with regard to
the goals of the Holocaust?
The Milgram Experiments
“I was just following orders”
The Milgram Experiments
The Milgram Experiments
http://www.youtube.com/watch?v=yr5cjyokVUs
The Milgram Experiments
“I was just following orders”
 Thinking Critically with Psychology
Research Ethics
(1) Obtain informed consent
(2) Protect them from harm
(3) Maintain confidentiality
(4) Debrief
 Thinking Critically with Psychology
Research Ethics
Is it Ethical to Experiment on
Animals?
 Chapter 1 Review
Why do we need psychological
science?
How do psychologists ask and answer
questions?
What are major steps in the research
process?
What are the major research methods
that psychologist use?
 Chapter 1 Review
Question(s) from textbook on material
not covered in class:
Statistical reasoning in everyday
life (pp. 36-39)