19.6 Psychology: Schools, Development & Personality

19.6 Psychology: Schools, Development & Personality

Quick Answer: Psychology approaches behavior through several major schools, each offering a different lens. Modern biopsychosocial models integrate them, recognizing that biology, cognition, and social context all shape behavior.

Major Schools of Psychology

• Psychodynamic (Freud, Jung, Adler) — unconscious drives, early childhood, intrapsychic conflict.
• Behavioral (Watson, Pavlov, Skinner) — observable behavior, learning principles, environmental determinism.
• Humanistic (Rogers, Maslow) — self-actualization, free will, unconditional positive regard; person-centered therapy.
• Cognitive (Beck, Ellis) — thoughts mediate emotion and behavior; cognitive restructuring for depression and anxiety.
• Biological (neuroscience, evolutionary) — behavior arises from brain, genetics, and natural selection.
• Sociocultural — behavior shaped by culture and social context.

Lifespan Development — Erikson

Erik Erikson described eight psychosocial stages, each a crisis resolving toward a virtue:

Adolescent identity formation is central; failure yields role confusion. James Marcia described identity statuses: diffusion, foreclosure, moratorium, achievement.

Personality Theories

Freud's structural model divides the psyche into the id (instinct, pleasure principle), ego (reality principle, mediating), and superego (morality). Defense mechanisms manage anxiety unconsciously — examples: repression (blocking unacceptable impulses from awareness), denial (refusing external reality), projection (attributing one's own unacceptable feelings to others), displacement (redirecting an impulse to a safer target — anger at boss expressed at family), rationalization (justifying behavior with logical-sounding reasons), sublimation (channeling impulses into socially valued activity — aggression into competitive sport, considered the most mature), reaction formation (expressing the opposite of the true feeling), and regression (reverting to an earlier developmental stage under stress).

Freud's five psychosexual stages — oral (0–1 yr, feeding; fixation → smoking/overeating), anal (1–3 yr, toilet training; fixation → anal-retentive or anal-expulsive traits), phallic (3–6 yr, Oedipus/Electra complex, resolved by identification with the same-sex parent), latency (6–12 yr, sexual impulses dormant), and genital (12+ yr, mature intimate relationships) — each can produce fixation if over- or under-gratified. Modern psychology treats the specifics as largely untestable, but the idea that early experience shapes adult personality remains influential.

Trait theories describe stable dispositions. Allport identified cardinal, central, and secondary traits. The Big Five (OCEAN) is the dominant model, validated across cultures:

Big Five traits are roughly 40–60% heritable; they predict outcomes (conscientiousness predicts academic and job performance; neuroticism predicts depression). Eysenck's PEN model (Psychoticism, Extraversion, Neuroticism) links traits to cortical arousal levels.

Other approaches: Maslow's hierarchy of needs (physiology → safety → belonging → esteem → self-actualization); Rogers' self-concept (real vs ideal self, congruence); Bandura's social-cognitive theory and reciprocal determinism (behavior, cognition, and environment interact); Mischel's person-situation debate and self-regulation.

Motivation and Emotion

Motivation energizes and directs behavior. Drive-reduction theory (Hull): homeostatic needs create drives. Arousal theory and the Yerkes-Dodson law: performance peaks at moderate arousal. Intrinsic motivation (internal) often exceeds extrinsic (rewards can undermine interest — the overjustification effect). Maslow and self-determination theory (Deci & Ryan: autonomy, competence, relatedness) emphasize growth needs.

Hunger and eating is the Bulletin's named example of a motivated behavior, and it is the one place the Behavioral Sciences block expects real endocrine detail. Short-term signals cycle with meals: ghrelin, released by the empty stomach, is the only orexigenic (hunger-promoting) gut hormone and peaks just before eating, while cholecystokinin (CCK), peptide YY, and GLP-1 rise after a meal and promote satiety. The long-term signal is leptin, secreted by adipose tissue in proportion to fat mass, which suppresses appetite; most human obesity involves leptin resistance rather than leptin deficiency, which is why leptin therapy helps only the rare congenital-deficiency patient. These signals converge on the hypothalamic arcuate nucleus, where NPY/AgRP neurons drive feeding and POMC neurons suppress it; classically the lateral hypothalamus initiates eating (lesions produce aphagia) and the ventromedial hypothalamus terminates it (lesions produce hyperphagia and obesity). Layered on top are non-homeostatic influences the exam likes to contrast with the biology: set-point theory and basal metabolic rate, learned meal timing, portion and variety effects, stress- and mood-driven eating, and cultural norms about what counts as food. Disordered forms — anorexia nervosa, bulimia nervosa, and binge-eating disorder — are diagnosed by DSM-5 criteria rather than by weight alone.

Emotion has physiological, expressive, and subjective components. The major theories:

• James-Lange — physiological arousal precedes emotion ("we feel sorry because we cry").
• Cannon-Bard — arousal and emotion occur simultaneously and independently.
• Schachter-Singer (two-factor) — arousal plus a cognitive label produces emotion.
• Lazarus — cognitive appraisal precedes emotion.

Universal emotions (Ekman): happiness, sadness, fear, anger, surprise, disgust — recognized across cultures via facial expression. The amygdala processes fear; the prefrontal cortex regulates emotion. Emotion regulation strategies include reappraisal (changing how one thinks about a stimulus, generally adaptive) and suppression (inhibiting expression, associated with higher physiological arousal and worse outcomes over time).

Stress activates the HPA axis (hypothalamus → pituitary → adrenal cortex → cortisol) and the sympathetic-adrenal-medullary axis (catecholamines). Hans Selye's general adaptation syndrome (GAS) describes three stages: alarm (sympathetic activation), resistance (sustained coping, elevated cortisol), and exhaustion (depletion, illness risk). Chronic stress impairs hippocampal function, suppresses immune response, and increases cardiovascular risk. Coping strategies are problem-focused (changing the situation) or emotion-focused (changing the response); resilience and social support moderate outcomes. Locus of control (internal vs external) also predicts coping effectiveness — an internal locus generally promotes active, problem-focused coping.