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PSY130 – Chapter 12 Personality: Development and Measurement

Personality: Key Definitions & Continuum

  • Personality = an individual’s consistent patterns of feeling, thinking, behaving.

  • Extraversion ↔ Introversion lie on a continuum.

    • Extraverts: prefer more social & sensory stimulation.

    • Introverts: prefer less social & sensory stimulation.

12.1 Personality & Behavior: Approaches and Measurement

  • Personality as Traits

    • Traits = relatively enduring characteristics influencing behaviour across many situations.

    • Explain behavioural consistency; allows prediction of future actions.

  • Representative trait list (see Table 12.1)

    • Authoritarianism

    • Individualism–collectivism

    • Internal vs. external locus of control

      - External vs. Internal locus of control: The degree to which individuals believe that outcomes are determined by external forces rather than by their actions.

    • Need for achievement

    • Need for cognition

    • Regulatory focus (promotion vs. prevention orientation)

    • Self-esteem

    • Sensation seeking - The tendency to seek out varied, novel, complex, and intense experiences, often linked to higher levels of curiosity and exploration.

Self-Report Measures

  • Must satisfy:

    • Reliability → scores remain stable over time.

    • Validity → measures the intended construct.

  • Challenge: \approx 18,000 English words describe personality → deciding which and how many traits matter.

Trait Pioneers

  • Shared assumption: traits are stable personality units; used statistical analysis of self-reports.

  • Allport: cardinal, central, secondary traits.

  • Cattell: source vs. surface traits; developed 16-PF instrument.

  • Eysenck: focused on biological/genetic origins; emphasized introversion–extraversion continuum.

Five-Factor Model (Big Five)

  • Cross-culturally shared, most researched contemporary model.

    1. Openness

    2. Conscientiousness

    3. Extraversion

    4. Agreeableness

    5. Emotional Stability (Neuroticism reversed)

  • Key findings

    • Conscientiousness → strongest universal predictor of job success.

    • Other factors predict sector-specific success.

    • Does not fully capture moral behaviour; translation quality & response bias can affect measurement.

Additional Trait Models

  • HEXACO = Honesty/Humility + the Big Five (Honesty/Humility–Openness–Conscientiousness–Extraversion–Agreeableness–Emotional Stability).

  • Myers-Briggs Type Indicator (MBTI)

    • 4 dichotomies → 16 types; most widely administered worldwide.

    • Lacks reliability & validity; treats traits as categories rather than continua.

    • Paid (\$49.95) vs. free Big Five/HEXACO inventories.

Situational Influences on Trait Expression

  • Some traits vary more (emotional stability, extraversion) vs. less (honesty, openness).

  • Aggregated behaviour across situations better predicted than single-situation behaviour.

Minnesota Multiphasic Personality Inventory (MMPI)

  • 338 questions ⇒ 51 subscales; detects personality & maladjustment.

  • Includes lie-detection items.

  • Used for high-responsibility roles (police, air-traffic control, pilots, clergy) & legal contexts (criminal courts, custody disputes).

Personality in the Workplace

  • I/O psychologists align traits with job requirements.

  • Conscientiousness = universal predictor; other traits vary by occupation (see Table 12.4).

Leadership & Traits

  • Leadership = directing/inspiring others toward goals.

  • Trait theories: certain personalities naturally lead.

    • Charismatic: enthusiastic, group-focused, self-sacrificing.

    • Transactional: clarify expectations, exchange rewards.

    • Transformational: articulate vision, intellectually stimulate, inspire followers.

The Barnum Effect

  • People accept vague, general personality descriptions as uniquely accurate.

12.2 Genetics of Personality

  • Gene = basic hereditary unit; influence but do not rigidly determine personality.

  • Instinct = species-specific biological urge.

  • Personality is polygenic; trait strengths vary within species.

Behavioural Genetics Methods

  • Family study: map trait within family tree.

  • Twin study: compare MZ vs. DZ twins on traits.

  • Adoption study: separate genetic from environmental contributions.

Molecular Genetics Techniques

  • Knockout studies in mice → modify/remove specific genes → observe effects on anxiety, aggression, learning, socialization.

  • Genome-Wide Association Studies (GWAS): match traits with common genetic markers across thousands of genomes.

Gene–Environment Interaction & Lifespan Change

  • Maturity principle: conscientiousness, agreeableness, emotional stability ↑ with age; extraversion ↓.

  • After \text{age} > 80: openness, conscientiousness, agreeableness, emotional stability tend to ↓.

  • Personality shaped by genetic influence + shared environment + non-shared environment.

12.3 History: Early Personality Theories

Psychoanalytic Theory (Freud)

  • Assumes unconscious mental activity drives behaviour; no free will.

  • Structural model:

    • Id: primitive impulses.

    • Ego: conscious decision-maker.

    • Superego: morality.

Defense Mechanisms (Table 12.5)

  • Displacement, Projection, Rationalization, Reaction formation, Regression, Repression (denial), Sublimation.

Psychosexual Development (Table 12.6)

  • Stages (oral → anal → phallic → latency → genital); controversial & weak empirical support.

Neo-Freudian (Psychodynamic) Thinkers

  • Maintain unconscious & early-experience focus; de-emphasize sexuality; more optimistic about adult change.

    • Adler: striving for superiority; inferiority complexes.

    • Jung: collective unconscious; archetypes; self-realization.

    • Horney: security as core motive; feminist critique of Freud; dependence on men, not anatomy, fuels female inferiority feelings.

    • Fromm: technology → alienation & disconnection.

Strengths & Limitations

  • Contributions: emphasized childhood, unconscious motives; influenced culture & therapy.

  • Limitations: poor empirical testability; psychosexual stages outdated; defense mechanisms lack robust data; unfalsifiability (any contradictory result dismissed as defense mechanism).

  • Some modern psychodynamic concepts have acquired empirical support.

Humanistic Psychology & Self-Actualization

  • Emerged 1950-60s as counter to psychoanalysis.

  • Emphasizes free will, innate goodness, growth motivation.

  • Key constructs

    • Self-concept = beliefs about who we are.

    • Self-esteem = positive feelings toward self.

    • Self-actualization = drive to realize fullest potential.

Maslow’s Hierarchy of Needs

  • Physiological → Safety → Love/Belonging → Esteem → Self-Actualization (pinnacle motive).

Carl Rogers & Unconditional Positive Regard

  • Leading humanist; person-centred therapy.

  • Unconditional positive regard: genuine, open, empathic acceptance of client → fosters growth.

  • Evidence: therapists using this approach have higher success rates.

Humanism → Positive Psychology

  • Humanistic ideas underpin modern positive psychology.

  • Positive thinking correlated with better relationships, life satisfaction, health outcomes.