Psychology 3051 Psychology 305A: Theories of Personality Lecture 3 1

Psychology 3052 Research Methods and the Trait Perspective 1. How are the reliability and validity of personality measures assessed? (continued) 2.What are traits? 3. What methods have been used to identify the traits that are most important in describing personality? 4.Has a comprehensive taxonomy of personality traits been developed? 2

By the end of today’s class, you should be able to: 2.distinguish between face, content, predictive, convergent, and discriminant validity. 3. determine which forms of reliability and validity are necessary for the assessment of distinct constructs distinguish between internal consistency, inter-rater reliability, and test-retest reliability. 3

5. describe factor analysis distinguish between the lexical, statistical, and theoretical methods of trait psychology. 4

5 2.Inter-rater reliability: Relevant for studies in which two or more individuals rate the participant on a given characteristic (S-, I-, or B-data). For S-data, the raters are coders scoring participants’ responses to interviews or unstructured questionnaires; for I-data, the raters are informants; for B-data, the raters are researchers. 5 How are the reliability and validity of personality measures assessed? (continued)

6 Reflects the degree to which the scores provided by different raters are consistent with one another (i.e., the degree to which there is consensus among raters). Involves calculating the correlation between the scores provided by different raters. 6

7 3.Test-retest reliability: Relevant for all types of measures (S-, I-, or B-data). Reflects the degree to which participants’ scores on one test administration are consistent with their scores on a second test administration. Involves calculating the correlation between participants’ scores on successive test administrations (e.g., their scores at time 1 and their scores at time 2). 7

8  Refers to the degree to which a measure assesses the construct it is intended to measure. Validity (or construct validity)  A measure that is reliable may or may not be valid; a valid measure must be reliable. 8

9  The validity of a measure may be established by demonstrating that it possesses one or more of the following forms of validity. 1. Face validity: Refers to the degree to which a measure appears to tap the construct under study. E.g., Rosenberg’s Self-Esteem Scale. All in all, I am inclined to feel that I am a failure On the whole, I am satisfied with myself 9

10 2. Content validity: Refers to the degree to which a measure assesses the underlying dimensions of the construct under study. E.g., Self-esteem Rosenberg’s Self-Esteem Scale: Assumes self-esteem is unidimensional. Harter’s Self-Perception Profile: Assumes self-esteem is multidimensional; assesses self-esteem related to scholastic competence, athletic competence, social acceptance, physical appearance and behaviour. 10

11 Content validity is assessed in one of two ways: (a) having experts judge the adequacy with which the measure assesses the underlying dimensions of the construct. (b)for questionnaire measures, factor analyzing participants’ responses to the items. Factor analysis is a procedure that identifies items that are highly correlated with one another; each group of highly correlated items reflects a single dimension of the construct under study. 11

12 3. Predictive validity (or criterion validity): Refers to the degree to which a measure is able to predict the likelihood or extremity of a behaviour that is theoretically related to the construct under study. E.g., A self-esteem measure that is high in predictive validity should be able to predict:  alcohol and drug use  persistence in the face of failure  number of sexual partners (i.e., sexual promiscuity) 12

13 4. Convergent validity: Refers to the degree to which a measure correlates with measures that assess conceptually-related constructs (i.e., constructs that are theoretically related to the construct of interest). E.g., A self-esteem measure that is high in convergent validity should be correlated with measures of:  depression  neuroticism  positive affectivity 13

14 5. Discriminant validity: Refers to the degree to which a measure does not correlate with measures that assess conceptually- unrelated constructs (i.e., constructs that are not theoretically related to the construct of interest). E.g., A self-esteem measure that is high in discriminant validity should not be correlated with measures of:  agreeableness  need for cognition  political attitudes (i.e., liberal vs. conservative) 14

15 Often, convergent and discriminant validity are examined simultaneously: DepNeurPosAffAgreeNCognPolatt SE

Psychology According to the trait approach, personality is best described as a constellation of traits (e.g., anxious, conscientious, outgoing). E.g., Peter is jealous. “Jealous” describes Peter’s behaviour. Traits are viewed as descriptive summaries of behaviour. What are traits? 16

Psychology What methods have been used to identify the traits that are most important in describing personality? 1. Lexical Method  Based on lexical hypothesis: “All important differences in personality are encoded in natural language.” Trait psychologists have used three methods to identify the traits that are most important in describing personality: 17

Psychology  Employs two criteria to identify the traits that are most important in describing personality: (a)Synonym frequency: E.g., Dominant vs. manipulative. 18

Psychology (b)Cross-cultural universality: E.g., Trait among the Yanomamo Indians of Venezuela: Unokai = trait ascribed to a male who has achieved manhood by killing another male. A comparable trait does not exist in any English- speaking culture. 19

Psychology Statistical Method  An atheoretical approach.  Typically, involves collecting data with structured questionnaires.  The resulting data are analyzed using factor analysis. 20

Psychology  Factor analysis examines the correlations between all pairs of items and identifies groups of items that are highly correlated with one another.  Each group of items that is identified is thought to reflect a single dimension of personality.  Each dimension is interpreted and labeled by the researcher (a highly subjective process). 21

Psychology E.g., Results of a Factor Analysis AdjectiveFactor 1Factor 2Factor 3 Humourous Amusing Popular Hard-working Productive Determined Imaginative Original Inventive “Extraversion”“Conscientiousness”“Openness”Factor label 22

Psychology  Factor analysis allows the researcher to reduce a large number of personality traits to a small number of personality dimensions.  Each dimension is thought of as a superordinate trait that encompasses several narrowly defined traits. 23

Psychology E.g., Results of a Factor Analysis AdjectiveFactor 1Factor 2Factor 3 Humourous Amusing Popular Hard-working Productive Determined Imaginative Original Inventive “Extraversion”“Conscientiousness”“Openness”Factor label 24

Psychology Theoretical Method  The traits that are most important in describing personality are identified on the basis of a pre-existing theory.  E.g., Psychoanalytic Theory Anal-expulsive personality type: Disorganized, hostile, destructive. Anal-retentive personality type: Stubborn, stingy, orderly. 25

Psychology Has a comprehensive taxonomy of personality traits been developed? Taxonomy: A classification system (e.g., Periodic Table of Elements). 26

Psychology Over the past century, dozens of taxonomies have been proposed for personality traits. E.g., Cattell’s taxonomy (16 PF) Eysenck’s taxonomy (Extraversion, Neuroticism, Psychoticism) Wiggins’ taxonomy (Interpersonal Circle) 27

Psychology In recent years, one taxonomy has been most influential—the Five Factor Model (FFM) or Big 5 taxonomy of personality traits. The FFM emerged from decades of research by dozens of researchers. This research combined the lexical and statistical methods. 28

Psychology Research Methods and the Trait Perspective 1. How are the reliability and validity of personality measures assessed? (continued) 2.What are traits? 3. What methods have been used to identify the traits that are most important in describing personality? 4.Has a comprehensive taxonomy of personality traits been developed? 29