Psychology 3051 Psychology 305: Theories of Personality Lecture 1.

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Psychology 305: Theories of Personality

Lecture 1

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Lecture 1

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?

Questions That Will be Answered in Today’s Lecture

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• A formal definition: “Personality is a dynamic organization, inside the person, of psychophysical systems that create the person’s 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”

What is Personality?

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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 can’t 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.

1. Synthesizing function: Theories should explain and organize

observations that have already been made.

2. 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 philosophy—a philosophy is broader than a theory.

2. a hypothesis—a hypothesis is more specific than a theory; a theory should generate hypotheses.

3. a taxonomy—a taxonomy is a classification system and does not generate hypotheses.

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How is Research Used to Test Theories?

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

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

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• Examples of operationalizations:

Construct: Physical healthOperationalization: Heart rate, blood pressure, cholesterol levels

Construct: AggressionOperationalization: Frequency and intensity of shocks given to a confederate

Construct: IntelligenceOperationalization: Scores on an IQ test

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Theories

Hypotheses

Operationalizations

Research

Observations

InteractiveRelationship

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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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Pretest

Group A

Group B

Random Assignment

Treatment A

Posttest

A Simple Experiment

Treatment B

Posttest

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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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Height

Weight

r = +1.00Positive Linear Relationship

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Criminal Activity

Education Level

Negative Linear Relationship

r = -1.00

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Exam Performance

Anxiety

Nonlinear or Curvilinear Relationship

r = 0.00

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An r = 0.00 would occur between two variables under the following conditions:

(a) The relationship between the variables iscurvilinear.

(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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Height

Weight

The Impact of Restricted Range on r

Insufficient variability to allow for a correlation to emerge

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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 B—this is referred to as the third variable problem.

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Example of the third variable problem:

Self-Esteem Academic Performance

ObservedRelationship, r = .30

??

Intelligence,Socioeconomic Status

TrueRelationship

TrueRelationship

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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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Subject Depression GroupNumber Score

6 3 Low9 28 Low1 30 Low

10 49 Low4 50 Low

---------------------------- Median Split --------------------------2 51 High5 53 High8 67 High3 75 High7 88 High

Example of loss of information associated with categorization:

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4. Case Studies

Involve the in-depth examination of the life of one person.

Assessment techniques include: ObservationInterviews Administration of standard personality testsAnalysis 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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People experience happiness when they have successfully influenced others’ opinions.

Experimental study.

Hypothesis Ideal Research Method

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Group A

Group B

Random Assignment

Treatment A

Posttest

A Simple Experiment

Treatment B

Posttest

Pretest

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People experience happiness when they have successfully influenced others’ opinions.

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

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

Experimental study.

Case study.

Correlational study.

Hypothesis Ideal Research Method

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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?

Questions That Were Answered in Today’s Lecture