Psychology of Personality
A survey of the major theoretical approaches to personality — psychodynamic, neo-analytic, humanistic, trait, biological, behaviorist, and social-cognitive — together with the methods used to measure personality and evaluate the theories themselves. Emphasis is on comparing what each tradition claims about the origin, structure, and stability of personality, and on judging those claims against evidence.
What personality is
Personality is the characteristic pattern of thoughts, feelings, and behaviors that distinguishes one person from another and shows some consistency across situations and time. Two commitments are packed into that sentence, and both are contested:
- Distinctiveness — personality is about individual differences. A trait everyone shares equally isn't a personality variable.
- Consistency — the pattern holds up across situations and over time. If behavior were purely situational, "personality" would explain nothing.
Some working vocabulary you'll use throughout the course:
- Trait — a relatively enduring disposition to behave a certain way (e.g., conscientiousness).
- State — a temporary condition (e.g., being anxious right now). Traits are dispositions; states are momentary.
- Character — the evaluative dimension of personality; judgments of worth or morality.
- Temperament — biologically-rooted individual differences visible early in life.
The person–situation debate
In Personality and Assessment (1968), Walter Mischel argued that trait measures rarely correlated above roughly r = .30 with actual behavior — the so-called "personality coefficient." If traits predicted so weakly, perhaps situations drove behavior instead.
The resolution was not a winner but a synthesis, interactionism: behavior is a function of the person and the situation together. Key repairs to the original critique:
- Aggregation. Single behaviors are unreliable; averaged across many occasions, trait–behavior correlations rise substantially. One measurement is noise; many are signal.
- Situation strength. Strong situations (a funeral, a red light) suppress individual differences. Weak, ambiguous situations let personality express itself.
- If–then signatures. Mischel's own later work showed people have stable conditional patterns — "warm with peers, hostile with authority" — which is consistency of a subtler kind.
- r = .30 is not small. It's typical of effect sizes throughout psychology, and it accumulates meaningfully over many decisions.
How personality is studied
Four broad data sources, remembered as LOTS:
| Source | What it is | Strength | Weakness |
|---|---|---|---|
| L — Life data | Records of actual outcomes (grades, arrests, salary) | Real-world consequences | Coarse; many causes |
| O — Observer data | Ratings by people who know the target | Multiple viewpoints | Observers see limited contexts |
| T — Test data | Standardized tests, lab tasks | Controlled, comparable | May lack realism |
| S — Self-report | The person describes themselves | Access to inner experience | Distortion, limited self-insight |
Three research designs:
- Case study — deep examination of one person. Rich hypotheses, poor generalization. Freud's method.
- Correlational — measure variables, quantify association. Handles natural variation, but correlation does not establish causation (third variables, reverse causation).
- Experimental — manipulate, randomize, compare. Supports causal claims, but many personality variables can't be assigned.
Judging a theory
A theory of personality is evaluated on:
- Verifiability / falsifiability — can it be tested and proven wrong?
- Comprehensiveness — how much does it explain?
- Parsimony — is it as simple as the data allow?
- Heuristic value — does it generate productive research?
- Applied value — does it help in therapy, work, education?
- Internal consistency — do its parts cohere?
Keep this list. The recurring exam task is not "what did Freud say" but "how does Freud's theory fare on falsifiability compared to the Big Five."