personality

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Chapter 2 Personality Assessment, Measurement, and Research Design

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Sources of Personality Data • Self-report data (S-data). • Observer-report data (O-data). • Test data (T-data). • Life-outcome data (L-data).

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Self-Report Data (S-Data)

Information provided by a person through a questionnaire or an interview. Individuals have access to a wealth of information about themselves that is inaccessible to anyone else. S-data personality tests. • Unstructured items: Open-ended. • Structured items: Response options are provided.

Limitations of S-data. • People may not respond honestly. • People may lack accurate self-knowledge.

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Observer-Report Data (O-Data) 1

Information provided by someone else about another person. • Key features. • Provides access to information not attainable through other

sources. • Multiple observers can be used to assess a person.

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Observer-Report Data (O-Data) 2

Strategies for selecting observers. Using professional personality assessors. Using people who actually know the target person. • Remain in a better position to observe target’s natural

behaviors than professional personality assessors. • Allows for the assessment of multiple social

personalities. • May be biased because of their relationship with the target.

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Observer-Report Data (O-Data) 3

Naturalistic versus artificial observation. Naturalistic observation. • Observers witness and record events that occur in the

normal course of the lives of participants. • Maintains an advantage of being able to secure

information in realistic context, but at the cost of not being able to control the events witnessed.

Artificial observation. • Occurs in artificial settings or situations. • Maintains an advantage of controlling conditions and

eliciting relevant behavior, but at the cost of sacrificing realism.

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Test Data (T-Data) 1

• Information provided by standardized tests or testing situations.

• Idea is to see if different people behave differently in identical situations.

• Situation is designed to elicit behaviors that serve as indicators of personality.

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Test Data (T-Data) 2

Limitations • Participants may try to guess what trait is being measured

and then alter their behavior to create certain impressions. • Difficult to know if participants define the testing situation

as intended by the experimenter. • Researcher might influence how participants behave.

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Test Data (T-Data) 3

Mechanical recording devices (for example, “Actometer” that is used to assess children’s activity). Strengths. • Unhampered by the biases of human observation. • Obtainable in naturalistic settings.

Disadvantage. • Few personality dispositions lend themselves to

mechanical assessment.

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Test Data (T-Data) 4

Physiological data. • Includes information about potential indicators of

personality such as a person’s level of arousal and reactivity to stimuli.

• Functional magnetic resonance imaging (f M R I). • Key benefit is that it is difficult to fake responses. • Disadvantage: Recording is constrained by a relatively

artificial laboratory situation.

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Test Data (T-Data) 5

Projective techniques. • Person is presented with an ambiguous stimulus and is

asked to describe what he/she sees. • Assumption is that the person “projects” his/her personality

onto the ambiguous stimulus. • Strength: May provide useful means for gathering

information about wishes, desires, and fantasies that a person is not aware of and could not report.

• Disadvantage: Uncertain validity and reliability.

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Life-Outcome Data (L-Data)

Information that can be gleaned from events, activities, and outcomes in a person’s life that are available for public scrutiny. • For example, marriage and speeding tickets.

Can serve as an important source of “real life” information about personality.

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Issues in Personality Assessment

Linking different data sources. Fallibility of personality measurement. • All sources of data have limitations. • Results that transcend data source (triangulation) are the

most powerful.

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Evaluation of Personality Measures

• Reliability. • Validity. • Generalizability.

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Reliability

Degree to which an obtained measure represents true level of the trait being measured. Measures of reliability. • Test-retest reliability. • Internal consistency reliability. • Inter-rater reliability.

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Response Sets

• Tendency of some people to respond to the questions on a basis that is unrelated to the question content.

• Called noncontent responding. • Acquiescence: Tendency to simply agree with the

questionnaire items, regardless of the content of those items.

• Extreme responding: Refers to the tendency to give endpoint responses.

• Social desirability: Tendency to answer items in such a way as to come across as socially attractive or likable.

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Validity

Degree to which a test measures what it claims to measure. Types of validity. • Face validity. • Predictive (criterion) validity. • Convergent validity. • Discriminant validity. • Construct validity.

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Generalizability

Degree to which a measure retains its validity across different contexts, including different groups of people and different conditions.

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Research Designs in Personality

• Experimental methods. • Correlational method. • Case study method.

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Experimental Methods

Used to determine causality. • Causality: Whether one variable influences another.

Two key requirements: • Manipulation of variables. • Ensuring that participants in each experimental condition

are equivalent to each other influences at the beginning of the study.

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Correlational Studies 1

• Correlation is a statistical procedure for determining whether there is a relationship between two variables.

• Designed to identify “what goes with what” in nature and not designed to identify causal relationships.

• Major advantage is that it allows us to identify relationships among variables as they occur naturally.

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Correlational Studies 2

Correlation coefficients vary from +1 (perfect positive relationship) through 0 (no relationship) to −1 (perfect negative relationships). Correlation does not indicate causation because of: • Directionality problem. • Third variable problem.

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Case Studies

In-depth examination of the life of a person. Advantages. • Can find out about personality in great detail. • Can give insights into personality that can be used to

formulate a more general theory to be tested on a larger population.

• Can provide in-depth knowledge about an outstanding individual, such as a political or religious personality.

Disadvantage. • Results based on the study of a single person cannot be

generalized to others.

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When to Use Experimental, Correlational, and Case Study Designs Each design has strengths and weaknesses. • Strength of one is weakness of another.

Design chosen by a researcher depends on the research question and goal of research. Taken together, the three designs provide complementary methods for exploring personality.

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Summary and Evaluation

• Decisions about data source and research design depend on the purpose of study.

• There is no perfect data source. • There is no perfect research design. • Some data sources and methods are better suited for

some purposes than for others.

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© McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.