Chapter 2 How is Personality Studied and Assessed

Chapter 2: How is Personality Studied and Assessed? This multimedia product and its contents are protected under copyright law. The following are prohibited by law: (1) Any public performance or display, including transmission of any image over a network; (2) Preparation of any derivative work, including the extraction, in whole or in part, of any images; (3) Any rental, lease, or lending of the program. Copyright © 2012 Pearson Education, Inc. All rights reserved.

Subjective Assessment � Measurement that relies on interpretation (unlike objective assessment) � Weaknesses ◦ Different observers may make different judgments � Strengths ◦ Complex phenomena may be examined and valuable insight gained Copyright © 2012 Pearson Education, Inc. All rights reserved.

Reliability (1) �The consistency of scores that are expected to be the same �Test-retest reliability ◦ Measure of consistency over time Copyright © 2012 Pearson Education, Inc. All rights reserved.

Reliability (2) �Internal consistency reliability ◦ Split-half reliability �The correlation between two halves of a test ◦ Cronbach’s coefficient alpha �The average of all possible split-half correlations Copyright © 2012 Pearson Education, Inc. All rights reserved.

Validity (1) �Construct validity ◦ The extent to which a test truly measures a theoretical construct �Convergent validity ◦ A measure is related to what it should be related to �Discriminant validity ◦ A measure is not related to what it should not be related to Copyright © 2012 Pearson Education, Inc. All rights reserved.

Validity (2) �Criterion-related validity ◦ The measure can predict important outcome criteria �Content validity ◦ The measure contains items that represent the entire domain of theoretical construct Copyright © 2012 Pearson Education, Inc. All rights reserved.

Item Selection � Items should be clear and relatively simple � Items should discriminate among test takers � Items should be intercorrelated ◦ But not so highly that they are redundant � The total score of the assessment should have a normal distribution ◦ Avoid ceiling and floor effects ◦ Be sensitive to variability across the range of scores Copyright © 2012 Pearson Education, Inc. All rights reserved.

Response Sets (1) �A bias in responding to test items that is unrelated to the personality characteristic being measured ◦ Acquiescence response set �“yes”, “agree, ” “true of me” ◦ Social desirability response set �The “good” or “correct” answer �The answer that reflects well on the test-taker Copyright © 2012 Pearson Education, Inc. All rights reserved.

Response Sets (2) �To reduce the problem of response sets ◦ Reverse-code some items ◦ Use neutral wording ◦ Include lie scales ◦ Use several different methods of assessment Copyright © 2012 Pearson Education, Inc. All rights reserved.

Ethnic and Gender Bias �A characteristic that is a strength in one group may be perceived as a weakness or deficiency in another �All tests make assumptions about the background of the test-taker �Use care in interpreting results ◦ Always consider the context Copyright © 2012 Pearson Education, Inc. All rights reserved.

Types of Personality Measures: Self-Report Tests �Usually pencil and paper tests �Most common type of test �Examples: ◦ Minnesota Multiphasic Personality Inventory (MMPI) ◦ Big-Five Inventory (BFI) ◦ Affective Communication Test (ACT) Copyright © 2012 Pearson Education, Inc. All rights reserved.

Types of Personality Measures: Q-Sort Tests � Person makes comparisons among his/her own characteristics � Uses a stack of cards, one characteristic per card � Sorts cards into piles indicating how descriptive each card is of him/her � Forced number of cards at each level ◦ Normalizes use of levels across test-takers Copyright © 2012 Pearson Education, Inc. All rights reserved.

Types of Personality Measures: Judgments by Others �Someone else answers questions about the person being measured �Some traits are easier to judge than others �Can use ratings from parents, friends, teachers, spouse, psychologists, etc. �Used for adults and children Copyright © 2012 Pearson Education, Inc. All rights reserved.

Types of Personality Measures: Biological Measures �Assumes that the nervous system is an important element of personality �Modern biological measures ◦ Electroencephalogram (EEG) �Can provide event-related potentials (ERPs) ◦ Positron emission tomography (PET) scan ◦ Magnetic resonance imagery (MRI) ◦ Functional magnetic resonance imagery (f. MRI) ◦ Hormonal levels ◦ Chromosomal analysis Copyright © 2012 Pearson Education, Inc. All rights reserved.

PET Scan Brain in REM Sleep (horizontal view, nose on top) Lightest areas have highest activity Copyright © 2012 Pearson Education, Inc. All rights reserved.

Types of Personality Measures: Behavioral Observations �Records the actual behavior of a person �Types of behavioral observations ◦ Simple counts of a specific behavior ◦ Coding videotaped interactions ◦ Electronic pagers Copyright © 2012 Pearson Education, Inc. All rights reserved.

Types of Personality Measures: Interviews �Unstructured interviews ◦ Typically yield rich information, but validity is questionable �Structured interviews ◦ More valid, but usually do not reveal individual nuances Copyright © 2012 Pearson Education, Inc. All rights reserved.

Types of Personality Measures: Expressive Behavior �The analysis of how people stand, move, speak, etc. �Includes ◦ ◦ ◦ the examination of: speech rate voice quality gaze patterns posture gestures Copyright © 2012 Pearson Education, Inc. All rights reserved.

Types of Personality Measures: Document Analysis/Life Stories �Involves the careful analysis of writings such as letters and diaries �Can be a very rich source of information �Examples: ◦ Allport’s “Letters from Jenny” ◦ Terman’s analysis of Galton’s letters Copyright © 2012 Pearson Education, Inc. All rights reserved.

Types of Personality Measures: Projective Tests �Present an unstructured or ambiguous stimulus, task, or situation � Test-taker provides an interpretation ◦ The goal is to gain access to unconscious motives and concerns �Examples: ◦ Draw-a-person test ◦ Rorschach Inkblot ◦ Thematic Apperception Test (TAT) Copyright © 2012 Pearson Education, Inc. All rights reserved.

Projective Test Example: Draw-a-Person Drawing by a nine-year-old in response to the prompt “Draw a person” Copyright © 2012 Pearson Education, Inc. All rights reserved.

Projective Test Example: Inkblot An inkblot stimulus similar to those used in the Rorschach Test. The test-taker is asked, “What do you see? ” Copyright © 2012 Pearson Education, Inc. All rights reserved.

Types of Personality Measures: Demographics and Lifestyle �Uses information about a person’s age, place of birth, gender, family size, etc. �Can help researchers understand people based on their everyday lives Copyright © 2012 Pearson Education, Inc. All rights reserved.

The Ethics of Personality Testing �Test results always contain some error ◦ However, this should not prevent us from using personality tests �Due to these errors, one must be careful ◦ when interpreting test results ◦ when choosing how to apply the results Copyright © 2012 Pearson Education, Inc. All rights reserved.

Research Designs �Common designs in personality research: ◦ Case Studies ◦ Correlational Studies ◦ Experimental Studies �Each has different benefits and drawbacks Copyright © 2012 Pearson Education, Inc. All rights reserved.