Psychology 305: Theories of Personality

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Psychology 305 Theories of Personality Lecture 1
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Lecture 1
Questions That Will be Answered in Todays Lecture

1. What is personality?
2. What is personality psychology?
3. Why study personality?
4. What is a theory?
5. How is research used to test theories?

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What is Personality?

• A formal definition Personality is a dynamic
  organization, inside the person, of
  psychophysical systems that create the persons
  characteristic patterns of behaviour, thoughts,
  and feelings.
• -- Carver Scheier, p. 5

• Noteworthy points about this definition

1. Psychophysical

2. Dynamic
3. Organization
4. Create
5. Characteristic patterns
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What is Personality Psychology?

• Every human being is like every other human
  being, like some other human beings, and like
  no other human being.
• -- Kluckhohn Murray, 1953

• This quote reflects the three levels of analysis
  in personality psychology

1. Human universals (e.g., desire to belong)
2. Group differences (e.g., sex differences)
3. Individual differences
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Why Study Personality?

• The study of personality serves three functions

1. Descriptive function
2. Explanatory function
3. Predictive function

• Predictive function is particularly important
  in
• applied settings.
• Examples Clinical settings, military settings,
  corporate settings.

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What is a Theory?

• Theory A proposed explanation or interpretation
  of the relations among conceptual variables or
  constructs.

• Construct A conceptual or hypothetical
  variable that cant be directly observed.

Examples of variables that are constructs
Intelligence, self-esteem, depression,
aggression.

Examples of variables that are not constructs
Hair colour, eye colour, weight, height, blood
pressure.
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• Theories serve two functions.

• Synthesizing function
• Theories should explain and organize
  observations that have already been made.

• Heuristic function Theories should generate
  predictions or
• hypotheses about phenomena that have not yet
  been observed.

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• A theory is not

1. a philosophya philosophy is broader than a
theory.
2. a hypothesisa hypothesis is more specific
than a theory a theory should generate
hypotheses.
3. a taxonomya taxonomy is a classification
system and does not generate hypotheses.
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How is Research Used to Test Theories?

• In order to test a theory, researchers must
  identify observable variables that reflect the
  conceptual variables or constructs of interest.

• Operationalization The translation of a
  conceptual variable or construct into a
  variable that can be observed and measured.

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• Examples of operationalizations

Construct Aggression
Operationalization Frequency and intensity of
shocks given to a confederate


Construct Physical health
Operationalization Heart rate, blood pressure,
cholesterol levels



Construct Intelligence

Operationalization Scores on an IQ test
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• Theories

Hypotheses

Interactive Relationship

Operationalizations
Research


Observations
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• Research Methods

1. Experimental Studies
? Designed to examine cause and effect
relationships between variables.
? Range from simple to complex.
? In simple experiments, there are only two
levels of the hypothesized causal variable or
independent variable (IV).
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• There are 4 steps involved in a simple
  experiment

(a) Participants are pretested on the
hypothesized effect variable or dependent
variable (DV).
(b) Participants are randomly assigned to one of
two groups.
(c) The two groups receive different treatments.
(d) The two groups are retested or posttested on
the DV.
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A Simple Experiment
Group A
Treatment A
Posttest
Pretest
Random Assignment
Group B
Posttest
Treatment B
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• ? Step (a) is often omitted.

Advantage of conducting a pretest Allows the
researcher to ensure that random assignment was
effective.
Disadvantage of conducting a pretest Pretest
sensitization.



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? Steps (b) and (c) are necessary to establish
causality. That is, participants must be
randomly assigned to groups and there must be at
least two levels of the IV included in the
experiment. Random assignment of participants
to multiple levels of an IV is referred to as
manipulation of the IV.
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2. Correlational Studies
? Designed to examine the extent to which 2
variables covary.
? The variables are not manipulated instead,
the naturally-occurring relationship between the
variables is examined.
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? Correlations are typically measured by the
Pearson product-moment correlation coefficient
(r).
? r measures the extent to which a linear
relationship exists between 2 variables.
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Positive Linear Relationship
r 1.00

• ? ? ? ? ?
• ? ?
• ? ? ?
• ? ?
• ? ?

Height
Weight
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Negative Linear Relationship

• ?
• ? ?
• ? ?
• ? ?
• ? ?
• ? ?
• ? ?

Criminal Activity
r -1.00
Education Level
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Nonlinear or Curvilinear Relationship
r 0.00

• ? ? ?
• ? ? ? ?
• ? ? ?
• ? ? ?
• ? ? ??
• ?? ?
• ? ? ? ?

Exam Performance
Anxiety
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• An r 0.00 would occur between two variables
  under the following conditions
• (a) The relationship between the variables
  is curvilinear.

(b) The variables are completely unrelated
(e.g., intelligence and snow boarding ability)
(c) The range of scores used for one or both
variables was restricted.
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The Impact of Restricted Range on r

• ? ? ? ? ?
• ? ?
• ? ? ?
• ? ?
• ? ?

Insufficient variability to allow for a
correlation to emerge
Height
Weight
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• Thus, the r between two variables may range in
  value from 1.00 to -1.00.

• Magnitude of r strength of the relationship
  between the variables.

• Sign of r ( vs. -) direction of the
  relationship between the variables.

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• In contrast to experiments, correlational
  studies do not allow researchers to determine
  causality.

• A correlation between variables A and B may
  occur because
• A causes B

B causes A
A third unmeasured variable accounts for the
observed relationship between A and Bthis is
referred to as the third variable problem.



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• Example of the third variable problem

Observed Relationship, r .30
Academic Performance

Self-Esteem

True Relationship
True Relationship
??



Intelligence, Socioeconomic Status
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• Remedies for the third variable problem
• (a) statistically control for the third
  variable (i.e., statistically hold the third
  variable constant for all participants).

(b) experimentally control for the third variable
(i.e., recruit participants whose scores on the
third variable are identical).



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• Correlational studies allow the researcher to
  use the full range of scores on the variable of
  interest. Therefore, they do not result in loss
  of information due categorization of
  participants into experimental groups.

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Example of loss of information associated with
categorization
Subject Depression Group Number Score
6 3 Low 9 28 Low 1 30 Low 10
49 Low 4 50 Low -----------------------
----- Median Split -------------------------- 2
51 High 5 53 High 8 67 High 3
75 High 7 88 High




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3. Case Studies
? Involve the in-depth examination of the life
of one person.

• Assessment techniques include
• Observation
• Interviews
• Administration of standard personality tests
• Analysis of written text

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Ted Bundy, 1946 - 1989
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Exercise Application of Research Methods

Construct Happiness.

Possible operationalizations

• Measure of life satisfaction.

• Measure assessing the frequency and intensity
  with which participants experience positive
  emotions (e.g., joy, contentment, excitement).

• Number of times participants smile.

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Hypothesis
Ideal Research Method

People experience happiness when they have
successfully influenced others opinions.
Experimental study.




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A Simple Experiment
Group A
Treatment A
Posttest
Random Assignment
Pretest
Group B
Posttest
Treatment B
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Hypothesis
Ideal Research Method

People experience happiness when they have
successfully influenced others opinions.
Experimental study.

People who report extraordinarily high levels of
happiness exhibit a unique constellation of
personality characteristics.
Case study.


People who experience high levels of happiness
tend to be more optimistic.
Correlational study.

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Questions That Were Answered in Todays Lecture

1. What is personality?
2. What is personality psychology?
3. Why study personality?
4. What is a theory?
5. How is research used to test theories?