Introduction to Psychology
Psychology: the science of
behavior and cognitive
processes
- Basically, psychology is
the study of everything we
do, feel, think, or
experience.
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
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

The Amazing Randi--Skeptic
thinking that does not
blindly accept
arguments and
conclusions
 examines
assumptions
 discerns hidden
values
 evaluates evidence
History
- Roots in Ancient Greece
(300sBCE)
- Philosophy (a study of
the processes regulating
thought, conduct, & reality)
combined with
- Physiology (the study of
the function of living
organisms)
What is the link between the mind
and the body?
 Is the mind connected to
the body or is it distinct?
 Are ideas inborn or is the
mind a blank slate filled
by experience?
Pre-scientific Psychology
Scientific Psychology
1879CE – Wilhelm Wundt (1832-1920)
founded the first formal laboratory for
research in psychology at the University of
Leipzig.
1883CE – G. Stanley Hall (1844-1924), a
student of Wundt, founded the first U.S.
psychology lab at John Hopkins University.
- In 1892, he founded the American
Psychological Assoc. (APA)
Approaches to Psychology
Structuralism: (W. Wundt &
Edward Titchener) examined
the structure of the mind,
analyzed the structure and
content of mental states by
introspection, and was
concerned with reducing
experience to its basic parts.
(1867-1927)
Functionalism: (William James)
proposed the study of how the
mind adapts us to our
environment.
- influenced by Charles
Darwin’s theories of evolution
and natural selection.
- felt that conscious experience
is adaptive and always
changing.
(1842-1910)
Charles Darwin
Natural selection

principle that
those inherited
trait variations
contributing to
survival will
most likely be
passed on to
succeeding
generations
On the Origin of Species was published in
1859.
- Darwin’s theory was that humans and
animals had evolved and changed.
- This theory inspired scientists to study
animals in order to understand human
behavior.
Psychodynamic: (Sigmund Freud, Carl
Jung, Karen Horney & Alfred Adler)
emphasized the study of unconscious
mental processes
- argued that people’s behavior is driven
by sexual urges, and that most emotional
conflicts date back to early childhood
experiences.
(1856-1939)
(1875-1961)
Behaviorism: (Ivan Pavlov, John Watson,
& B.F. Skinner) stressed the study of
observable behavior, not unobservable
consciousness.
(1878-1958)
(1904-1990)
Biological: (James Olds, Roger Sperry, &
George Miller) focused on the biological
events and processes that underlie
behavior
(1922-1976)
(1913-1994)
Humanistic: (Carl Rogers & Abraham
Maslow) stressed that humans have
enormous potential for personal growth.
- emphasized importance of free will, the
human ability to make choices, and the
uniqueness of the individual.
(1902-1987)
(1908-1970)
Cognitive: (Jean Piaget, Noam Chomsky,
Herbert Simon, & Ulric Neisser) studied
internal, mental representations that are
used in perceiving, remembering, thinking,
and understanding
(1896-1980)
(1928- )
Women in Early Psychology
Margaret Floy Washburn (18711939)
- first American woman to earn a
PhD in psychology
Mary Whiton Calkins (1863-1930)
- first woman president of the
APA
Research Methods

Psychological research is based on the scientific method, which
consists of:
1) defining a research problem
(Identifying factors associated with depression)
2) proposing a hypothesis and making predictions
(People with low self-esteem are apt to feel more depressed than
those with higher self-esteem.)
3) designing and conducting a research study
4) analyzing the data
5) communicating the results & building theories about
behavior
(Low self-esteem contributes to depression.)
Research Process
Research Terminology



Population - all members of a class or set from
which a smaller sample may be drawn and about
whom the researcher wants to draw conclusions
Sample - a subset of a population selected to
participate in a study
- All of the participants in a research study make up
the sample.
Random Sample - a sample in which every member
of the population being studied has an equal chance
of being picked for inclusion in the study





Biased Sample - when every member of the
population does not have and equal chance of being
chosen
Stratified Sample - one in which every relevant
subgroup of the population is randomly selected in
proportion to its size
(major subgroups in a high school)
Participant/Subject - an individual who is actively
participating in a research study
Replications - research studies that are repeated,
often under different conditions, in order to ensure
the reliability of the results
(Cold Fusion)
Generalizability - the possibility of applying
conclusions drawn about a research sample to the
entire population being studied
The Experiment
> Psychologists use experiments to determine cause
and effect relationships.
> An experiment requires that researchers
systematically manipulate or control one or more
variables and then observe how the subjects
respond to this manipulation.
 Independent Variable - the variable that is
manipulated
 Dependent Variable - the response that is measured
after the manipulation of the independent variable
Operational Definition - definition of a variable
in terms of the set of methods or procedures
used to measure or study that variable
(Emily Rosa’s Therapeutic Touch Experiment)
IV – random placement of Emily’s hand 2”
above either the right or left hand of TT
practitioners, whose vision is obscured
DV – TT practitioners will respond with “right” or
“left” to indicate the hand above which Emily
is holding hers; the response will be marked
correct or incorrect

Emily Rosa’s Experiment 1996





Confounding Variable - a stimulus other than the
variable an experimenter explicitly introduces into a
research setting that affects a participant's behavior
Experimental Group - the group that is exposed to
the manipulation of the independent variable
Control Group - the group not exposed to the
manipulation of the independent variable
Random Assignment - ensured that each participant
has an equal chance of being assigned to any one
of the groups
Quasi-Experiment - when participants are not
randomly assigned to groups





Subject Bias - when research participants' behavior
changes because they know they are being studied
or because of their expectations
Placebo - an inactive substance given in place of a
drug in psychological research.
Placebo Effect - occurs when a participant believes
s/he is experiencing a change due to the
administered drug, which is really a placebo.
(ie. antibiotics given for viruses)
Researcher Bias - occurs when the expectations of
the researcher influence what is recorded or
measured.
Double-Blind Technique - used to control for both
subject and researcher biases. Neither the subjects
nor the researcher measuring the dependent
variable know who is assigned to which group in an
experiment.
Hypothesis
X amount of sleeping pills helps the healthy
person with insomnia to sleep better.
Independent Variable
Groups
Dependent Variable
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.
Nonexperimental Methods
> These methods do not include the systematic
manipulation of variables by the researcher and, thus,
cannot be used to discuss cause-and-effect
relationships.
 Correlational Research - this involves measuring two (or
more) variables in order to determine if they are related.
 Positive Correlation - occurs when the value of one
variable increases in value as the other variable also
increases in value.
 Negative Correlation - occurs when there is an inverse
relationship between the variables measured; as the
value of one increases, the value of the other decreases.

Correlation Coefficient - this is a number that
represents the strength of the relationship
between the variables measured.
- It can range in value from zero to positive or
negative one.
- A correlation coefficient of zero indicates no
relationship between the variables measured.
- A correlation coefficient of one (+ or -)
indicates a perfect relationship between the
two variables: you can predict one variable
perfectly by knowing the value of the other.
Correlation
Perfect positive
correlation (+1.00)
No relationship (0.00)
Perfect negative
correlation (-1.00)
Scatterplots, showing patterns of correlations
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
Warning!

Even if a strong correlational coefficient is
found, however, cause-and-effect
conclusions cannot be drawn because there
was no systematic manipulation by the
researcher.
(True statement: “The taller a person is the
better reader s/he is.”)
How could this be true?
*Third Variable: age [older = taller]*


Another true statement: “According to a state
by state analysis, there is a predictable
pattern of teen births in this country. The
higher the temperature, the higher the
likelihood that teenagers will become
pregnant.”
*Third Variable: education*
[Southern states tend to teach abstinence,
while Northern states tend to teach
contraceptive use.]
Also true: “As ice cream sales increase, so
does violent crime.”
Correlation
Three Possible Cause-Effect Relationships
(1)
Low self-esteem
could cause
Depression
or
(2)
Depression
could cause
Low self-esteem
or
(3)
Distressing events
or biological
predisposition
Low self-esteem
could cause
and
Depression

Illusory Correlation
- prescient dreams (You dream & it happens.)
Dream
Yes
No


Naturalistic Observation - a research method
that occurs in a natural setting that has not
been manipulated by the researcher
- The researcher systematically observes and
records what occurs in an unobtrusive
manner.
- This is done so that the behavior of the
subjects being tested is not altered.
Interobserver Reliability - the amount of
agreement between two (or more) observers
who simultaneously observe the same event


Case Study - an in-depth study of a single
subject or a small group
- It can include interviews, observation, and test
results.
- It is often used to study unique or
irreproducible situations. (ie. Genie)
Survey Method - this method of collecting data
requires the researcher to ask a group of
people about thoughts, behaviors, or opinions.
- Data is collected through questionnaires or
interviews.
(David Duke election)
Survey
Comparing Research Methods
Method
Experiment
Strengths
Weaknesses
Can draw cause-and-effect
Sampling errors.
conclusions.
Often hard to generalResearcher has control.
ize to real world.
----------------------------------------------------------------------------------------------Correlation
Can study real world behavior. Cannot determine
Can determine relationships.
cause & effect.
----------------------------------------------------------------------------------------------Naturalistic
Can gather information in its
Cannot determine
Observation
usual setting as it naturally
cause & effect.
occurs.
Observer bias poss.
Incorrect interpretation
of behaviors.
Comparing, cont’.
Method
Case Study
Strengths
Intensive information can be
gathered about individuals.
Insight into unique situations.
Weaknesses
Cannot determine
cause & effect.
May not be able to
generalize information
gathered to others.
Biased sample poss.
----------------------------------------------------------------------------------------------Survey
Large amounts of information Cannot determine
can be gathered from many
cause & effect.
people in a relatively short
Biased sample poss.
period of time.
Questions might not
be reliable or valid.
Statistics
 Statistics are used in psychology to do the




following tasks:
1) summarize or describe large amounts of
data;
2) compare individuals or groups in a
number of ways;
3) determining if behaviors are related - vary
together/correlated;
4) predict future behavior using current
information.
Two Random Sequences
 Your chances of
being dealt
either of these
hands is
precisely the
same: 1 in
2,598,960.
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
Descriptive Statistics
> statistics that summarize the major characteristics of an
array of scores.
 A) Measures of Central Tendency (the middle of a
distribution of scores)
 1) Mean - this is derived by adding all scores and
dividing by the number of scores.

2) Mode - this indicates the most frequent
score in an array of scores.

3) Median - this indicates the midpoint of an array of
scores (half of the scores are located at or above
this score and half of the scores are located at or
below this score).
 B) Measures of Variability (relates to how
dispersed the scores are)

1) Range - the difference between the
highest and the lowest scores in a
distribution of scores.

2) Variance - the average squared distance
between each score and the mean.
(squaring eliminates negative numbers)

3) Standard Deviation - the average
distance between each score and the mean.
(this is the square root of the variance)
 C) The Normal Curve
 (Many psychological characteristics are


distributed in this manner).
1) Sixty-eight percent of scores in a
normal distribution fall within one
standard deviation of the mean, either
above or below it.
2) Ninety-six percent of scores in a
normal distribution fall within two
standard deviations of the mean, either
above or below it.
Skewed Distributions
Positive
Mean > Median
Negative
Mean < Median
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