Theoretical and measurement issues in trait psychology | |
Chapter OutlineTheoretical and Measurement Issues in Trait Psychology
Meaningful Differences Between Individuals
- There are meaningful differences between individuals (traits psychology is also called differential psychology)
- People differ in amounts of traits, and differences can be accurately measured
- According to trait psychologists, every personality is the product of a combination of a few basic, primary traits
Consistency Over Time
- Research indicates consistency over time for broad traits
- Although consistent over time, how a trait is manifested in behavior might change over time
- How can there be consistency in a trait if it is known to change with age (e.g., impulsivity)? Focus on the rank order differences between people
Consistency Across Situations
- Trait psychologists traditionally assumed cross-situation consistency
- If situations mainly control how people behave, then the existence or relevance of traits questionable
- Hartshorne and May (1928): Low cross-situation consistency is in honesty, helpfulness, self-control
- Mischel (1968): Personality psychologists should abandon their efforts to explain behavior with traits, focusing instead on situations
- Situationism: If behavior varies across situations, then situational differences and not personality traits determine behavior
- Mischel's (1968) critique encouraged debate in personality psychology about the importance of traits compared to situations in causing behavior
- Both sides tempered views: Trait psychologists acknowledged the importance of situation, and situationists acknowledged the importance of traits
- Debate led to two lasting changes: Focus on person-situation interaction and practice of aggregation
Person-Situation Interaction
- Two possible explanations for behavior:
- Behavior is a function of personality traits
- Behavior is a function of situation
- Integration: Personality and situation interact to produce behavior
- Differences between people make a difference only under certain circumstances
- Situational specificity: Certain situations can provoke behavior that is out of character for an individual
- Strong situation: Situations in which most people react in a similar way (e.g., grief following loss of loved one)
- When situations are weak or ambiguous, personality has its strongest influence
- Three additional ways in which personality and situation interact to produce behavior
- Selection: Tendency to choose or select situations in which one finds oneself, as a function of personality
- Evocation: Certain personality traits may evoke specific responses from others
- Manipulation: Various means by which people influence the behavior of others; tactics of manipulation vary with personality
Aggregation
- Longer tests are more reliable than shorter ones and are better measures of traits
- Single behavior or occasion may be influenced by extenuating circumstances unrelated to personality
- Aggregation implies that traits are only one influence on behavior
- Aggregation also implies that traits refer to the person's average level
- Thus, personality psychologists will never be good at predicting single acts or single occasions
Measurement Issues
- Trait approach relies on self-report surveys to measure personality
- Personality psychologists assume that people differ in the amounts of various traits, and so a key measurement issue is determining how much of trait person has
- Traits are often represented as dimensions along which people differ
- Trait psychologists are aware of and address circumstances that affect accuracy, reliability, validity, and utility of self-report trait measures
Carelessness
- Method for detecting such problems is an infrequency scale embedded in test
- Infrequency scale contains items that most people answer in a particular way
- If a participant answers differently than most, this suggests carelessness
- Another method for detecting carelessness is to include duplicate items spaced far apart in the survey—if the person answers the same item differently, this suggests carelessness
Faking on Questionnaires
- "Fake goodÓ: Attempt to appear better off or better adjusted than one is
- "Fake badÓ: Attempt to appear worse off or less adjusted than one is
- Method to detect is to a devise scale that, if answered in particular way, suggests faking
Response Sets
- Extreme responding: Tendency to give endpoint responses
- Social desirability: Tendency to answer items in such a way so that one comes across as socially attractive or likable
- Two views on social desirability:
- Represents distortion and should be eliminated or reduced
- Resolved by (1) measuring and statistically removing, (2) designing surveys that are less susceptible to this response set, or (3) using forced-choice format
- Valid part of other desirable personality traits, such as agreeableness, and should be studied
- Self-deceptive optimism versus impression management
Personality and Prediction
- Whether someone does well in an employment setting may be determined, in part, by whether a person's personality traits mesh with job requirements
- Personality traits may predict who is likely to do well in particular job, so it makes sense to select people for employment based on measures of traits
- But using tests to select employees has limitations and potential liabilities
- Lawsuits have challenged the use of tests on the grounds ranging from discrimination, to invasion of privacy, to freedom of religion
- Most employers receive overall test scores, however, not the applicant's answers to specific questions
- In 1978, the EEOC standardized federal guidelines for the use of tests in employment selection
- Two main concerns that the employer must satisfy to use for employment selection
- Test must predict performance on a specific job or jobs like the one people are being selected for
- Test must not be biased or have "undue impactÓ on persons from protected groups, such as women and minorities
Personnel selection: Choosing the Right Person for Job as Police Officer
- Personality tests frequently used to screen out "wrongÓ individuals from a pool of applicants for police officers
Educational selection: The Graduate Record Examination (GRE) and Success in Graduate School
- Most graduate schools require applicants to take the GRE, and most schools use GRE scores to some degree in deciding whom to accept into program
- GRE is an aptitude test, thought to reflect intelligence or the capacity to learn
- Many studies have been conducted to assess the degree to which GRE scores predict success in psychology graduate school
- Meta-analyses reveal that GRE scores do predict success in graduate school, but correlations are only modest (.15 to .40)
- Four arguments for why GRE scores can be useful, even though they only modestly predict success in graduate school
- Even small increments in predictability above chance can be useful
- Costs of failing to select the right people into graduate school can be high
- GRE scores can be useful if used with appropriate criterion (i.e., what want to predict)
- Criterion problem: Concerns how we define and measure the criterion we want to predict
- Validity of GRE depends on which criterion used to define success in graduate school—if defined as obtaining Ph.D., GRE scores are valid predictors
- Research indicates that, without range restriction, correlations between GRE scores and success in graduate school are high, ranging from .30 to .70
- Range restriction affects correlation
- When two variables are correlated with each other, the size of correlation depends, in part, on whether each variable spans full range in the sample
- Violation occurs when participants are selected on the basis of one score, and then that score is correlated with another variable on which participants have been measured
- Correlation between two variables will shrink as the range of scores on one (or both) variables is restricted
A Closer Look: Integrity Tests
- Integrity tests are surveys designed to assess whether a person is generally honest or dishonest; replaced polygraph
- When assessed against the "big fiveÓ personality traits, integrity is the combination of high conscientiousness, high agreeableness, and low neuroticism
- Integrity tests can be a valuable addition to other measures used in employment selection
Summary and Evaluation
- Hallmark of trait perspective is the emphasis on the differences between people
- Traits psychologists assume that people will be relatively constant over time and across situations in behaviors, because of their differences in various traits
- Traits are more likely to influence a person's behavior when the situation is weak and ambiguous and doesn't push for conformity from all people
- Personality traits refer to the average tendencies in behavior
- Trait psychologists are interested in the accuracy of measurement
- Interest in measurement and prediction has led trait psychologists to apply these skills to the selection or screening of job applicants and other situations where personality might make a difference
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