PSYC 1000 Lecture 48

Personality Humans have a fascination for trying to describe and understand individual differences –Precedes psychology as a formal discipline –Astrology, palmistry etc. However, many of the concepts that we have covered in this course have assumed that humans behave and think similarly (e.g. learning, memory, perception)

Personality –Complex set of psychological qualities that influence an individual’s characteristic patterns of behaviour across different situations and over time –Theories of personality used to both understand and predict behaviour –Approaches classify people according to types or traits of personality –Does inconsistent behaviour = unstable personality? Consistency paradox

The Trait Perspective Exploring Traits –Characteristic pattern of behavior; Disposition to feel and act, as assessed by self-report inventories and peer reports –Old idea: Ancient Greek physician Galen (C A.D.) thought personality reflected four humors (fluids) Yellow Bile: bad temper, irritability (Choleric) Black Bile: gloomy, pessimistic (Melancholic) Phlegm: sluggish, non-excitable (Phlegmatic) Blood: cheerful, passionate (Sanguine) –Other discredited ideas E.g., Sheldon: Ectomorph, Mesomorph, Endomorph

Myers-Briggs Type Indicator –Based on Jung’s personality types (right) –Popular in Education, Business, … –Empirical evidence does not (yet?) warrant extensive use Eysenck Two-Factor Model –Personality measure (more later) –Factor Analysis identified two dimensions Extraversion - Introversion Emotional Stability - Instability –Perhaps related to frontal lobe and other brain function

Structure of Personality Traits Hans and Sybil Eysenck used two primary personality factors as axes for describing personality variation

Biology and Personality –Brain Processes Extroverts may seek stimulation because normal brain arousal is low: e.g., frontal lobes involved in behavior inhibition less active in extraverts –Stimulation seeking –Ritalin is a stimulant that is prescribed for individuals with attention deficit hyperactivity disorder (ADHD) –Genes and personality Genetic aspects of early temperament Heritability of some personality traits high –Behavioural genetics shows stronger correlation for MZ twins vs. DZ twins on personality characteristics Animals and personality –Selective breeding for certain traits (e.g. Labs are “friendly” dogs.

Assessing Traits Personality Inventory –Questionnaire: people respond true-false or agree- disagree to items designed to measure wide range of feelings and behaviors –Used to assess selected personality traits Empirically Derived Test –Test developed by testing pool of items and selecting those that discriminate between groups Based on normative data –e.g., Inmates vs. Non-inmates, Schizophrenics vs. Non-schizophrenics, … –Such as MMPI

Minnesota Multiphasic Personality Inventory (MMPI) –Most widely researched and clinically used of all personality tests –Originally developed to identify emotional disorders i.e., discriminate different groups Still considered its most appropriate use –Now used for many other screening purposes

MMPI –Over 500 statements, indicate True or False for you –Validity scales Lie, Frequency, Omissions, Consistency –10 clinical scales Depression, Anxiety, Psychopathic deviant, … –Numerous supplementary and content scales Different facets of Schizophrenia, Alcohol Abuse, … –Empirically derived scales Also measures 5-Factor model (later) –More rational approach to test construction

Assessing Traits: MMPI-2

Assessing Traits Rational Test Construction –Define personality trait of interest –Generate items designed to assess that trait Positively and negatively worded to avoid response bias –Administer to large samples along with other measures (e.g., existing scales, measures of response bias, different traits) Assess internal consistency Assess validity: predictive, discriminative, construct

Psychopathy defined as constellation of affective, interpersonal, and behavioral characteristics including egocentricity; impulsivity; irresponsibility; shallow emotions; lack of empathy, guilt, or remorse; pathological lying; manipulativeness; and persistent violation of social norms and expectations Sample Items? –(+) If I feel like doing something, I do it. –(-) I don’t like to hurt other people’s feelings. –… Generally better assessed by clinical interview –Can be manipulated by lying.

Structure of Traits Big Five Personality Factors –Based on factor analysis of words related to personality, of personality inventory items, … –5 factors McCrea and Costa (1986): Emotional Stability, Extraversion, Agreeableness, Conscientiousness, Openness –Evaluation Reliability: Traits stable in adulthood Validity: predict marital satisfaction, work habits, … About 50% of variation due to heredity Appear to apply across cultures, with modest changes

Validity of Five Factor Model School and Job Performance –Conscientiousness and Openness predict school performance –Conscientiousness predicts general job performance –Extraversion predicts success in sales and management –Openness associated with creative performance Physical and Psychological Well-being –High Conscientiousness better health and longevity –Low Agreeableness / High Neuroticism health risk factors –Low Agreeableness / Conscientiousness predict juvenile delinquency –Neuroticism / Low Conscientiousness predict internalizing disorders –Neuroticism related to vulnerability and depression Other –Agreeableness associated with helping others and donating to charity