Personality Psychology: Origins, Theories, Stability, and Assessment

Comprehensive vocabulary flashcards covering the origins, theories, stability, and assessment methods of personality psychology.

Personality (Allport's Definition)

The dynamic organization within the individual of those psychophysical systems that determine characteristic behavior and thought (Gordon Allport, 1961).

Personality Trait

A relatively stable, enduring disposition or tendency that shapes generalized patterns of thinking, feeling, and behaving across situations, rather than moment-to-moment actions.

Nomothetic Approach

An approach to studying personality that focuses on general laws, universal dimensions, and group comparisons using standardized measures (such as questionnaire trait scores) to place individuals on common continuums.

Idiographic Approach

A person-centered approach that studies the unique individual case in depth, emphasizing personal meaning, life context, and qualitative configurations of characteristics that cannot be reduced to numerical scores.

Classic Twin Study (Loehlin & Nichols, 1976)

An investigation of $850$ pairs of twins establishing that identical (monozygotic) twins share an average personality correlation of $0.50$, whereas fraternal (dizygotic) twins show an average correlation of $0.28$, demonstrating substantial genetic influence.

Heritability (Personality)

The proportion of observable variation in a trait across a population that is attributable to genetic differences, typically estimated between $40\text{--}60\%$ for personality traits (not the percentage of an individual's trait determined by genes).

Unshared Environment

Unique environmental experiences that differ between siblings raised in the same home—such as distinct peer groups, teachers, illnesses, birth order, and differential parental treatment—accounting for approximately $40\text{--}50\%$ of personality variation.

Shared Environment

Common environmental factors shared by siblings reared together (e.g., family socioeconomic status, parenting philosophy, neighborhood), which surprisingly account for only $0\text{--}10\%$ of trait variation between individuals.

Temperament

Biologically based, broad behavioral tendencies that are evident in infancy, largely innate, and display high stability across the lifespan, serving as the biological foundation from which narrower personality traits develop.

Three Dimensions of Infant Temperament

The core biologically based infant traits identified as activity level (overall physical energy and movement), emotionality (the intensity and quality of emotional reactions), and sociability (the tendency to seek or avoid social contact).

Inhibited vs. Uninhibited Temperament (Kagan)

The developmental classification of infants into high-reactive ($20\%$; over-aroused, fearful, inhibited) versus low-reactive ($40\%$; under-aroused, calm, uninhibited) profiles that emerge within the first $4\text{ months}$ and persist over time.

Amygdala (in Temperament)

The limbic structure whose heightened reactivity and lower activation threshold to unfamiliar stimuli characterize inhibited temperaments, showing functional preservation from infancy to adulthood (Schwartz et al., 2003).

Person–Environment Fit

The reciprocal process through which an individual's innate temperament and personality traits influence the selection of compatible environments and social roles, matching individual tendencies to environmental affordances.

Five Factor Theory (The Big Five)

A comprehensive trait taxonomy (McCrae & Costa, 1999) describing personality along five continuous dimensions: Openness to experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism (OCEAN).

Hierarchical Organisation of Traits

The structural model where a broad overarching trait (e.g., extraversion) is subdivided into distinct facets (e.g., sociable, lively, assertive), which produce habitual behavioral tendencies and concrete moment-to-moment behaviors.

Biological Trait Theory (Eysenck)

Hans Eysenck's (1967) model proposing that personality is organized along three biologically rooted dimensions: Introversion/Extraversion, Neuroticism/Emotional Stability, and Psychoticism/Constraint.

Arousal Hypothesis of Extraversion

Eysenck's theory that introverts possess higher resting reticular arousal and avoid excessive stimulation, whereas extraverts possess chronically low baseline arousal and actively seek novel, stimulating experiences to achieve optimal arousal.

Behavioural Approach System (BAS)

The neurobehavioral 'go' system in Gray's Revised Reinforcement Sensitivity Theory that regulates sensitivity to rewards and governs approach behavior, corresponding closely to extraversion.

Behavioural Inhibition System (BIS)

The neurobehavioral 'slow down' system in Gray's rRST that responds to goal conflict, ambiguity, or cues of punishment by increasing anxiety, vigilance, and risk assessment.

Fight-Flight-Freeze System (FFFS)

The neurobehavioral 'stop or escape' system in Gray's rRST that mediates defensive avoidance and active escape to protect the organism from imminent threat or punishment.

Humanistic Approach to Personality

A perspective emphasizing the whole person, subjective conscious experience, free will, agency, and an innate orientation toward personal growth and self-actualisation.

Unconditional Positive Regard

Carl Rogers's core therapeutic and developmental condition of accepting and valuing an individual without evaluation or stipulations, fostering congruence and authentic psychological growth.

Conditions of Worth

Expectations or premises learned in childhood (e.g., being valued only when behaving properly) that cause individuals to deny aspects of their true self, producing incongruence between self-concept and experience.

Expectancy-Value Theory (Rotter)

Julian Rotter's (1954) cognitive framework stating that the likelihood of engaging in a behavior (behavior potential) is determined jointly by the expectancy that it will produce a specific reinforcement and the subjective value of that reinforcement.

Locus of Control

An individual's generalized belief regarding whether outcomes are determined internally by their own effort and actions (internal) or externally by luck, fate, or powerful others (external).

Reciprocal Determinism

Albert Bandura's (1986) social-cognitive model stating that personality and functioning emerge from the continuous, bidirectional interaction between personal factors, behavioral factors, and environmental influences.

Situationism

The theoretical position initiated by Walter Mischel (1968) arguing that human behavior is driven primarily by situational factors rather than stable underlying traits, challenging the consistency of personality.

Interactionism

The consensus framework resolving the consistency controversy by stating that behavior is an interactive function of both internal dispositions and external situational contexts ($\text{person} \times \text{situation}$).

Situation Strength (Strong vs. Weak Situations)

The degree to which an environment dictates behavioral norms: strong situations (e.g., an examination hall) suppress trait variation through strict rules, whereas weak situations (e.g., an informal social gathering) allow individual personality differences to emerge freely.

Rank-Order Stability

The maintenance of an individual's relative trait standing compared to peers over time across the lifespan, which is lowest in infancy ($0\text{--}2\text{ years}$, approximately $0.35$) and highest after age $50$ (exceeding $0.70$).

Mean-Level Change

The normative, population-wide fluctuation in the absolute average score of a personality trait across the lifespan, allowing individuals to change in level while maintaining rank-order position.

Rank-Order Stability vs. Mean-Level Change

The dual developmental trajectory showing that even as an entire cohort experiences mean-level increases in a trait (such as conscientiousness over adulthood), individuals retain their relative percentile rankings compared to one another.

Maturity Principle

The observed developmental trend whereby individuals typically increase in emotional stability, conscientiousness, and agreeableness as they transition through adulthood.

Social Investment Principle

The theory that adopting and committing to mature social roles (e.g., career, marriage, parenthood) demands specific behaviors and routines that ultimately alter an individual's enduring personality traits.

Travel and Personality Change (Zimmermann & Neyer, 2013)

A longitudinal study showing that university students studying abroad experienced significant increases in openness and agreeableness, and steeper decreases in neuroticism compared to non-traveling peers.

Universality of the Big Five (Schmitt et al., 2007)

A global cross-cultural study of $17{,}837$ participants across $56$ nations confirming that the Five Factor structure replicates robustly across diverse cultures and languages, despite modest regional score variations.

Reference Group Effect & Modesty Bias

Measurement artifacts in cross-cultural self-report research where participants rate themselves relative to regional peers rather than a universal standard, or alter self-descriptions to conform to cultural self-presentation norms.

Projective Measures

Personality assessment instruments in which respondents interpret ambiguous stimuli, presumed to uncover unconscious motives, defenses, and inner conflicts by filling in narrative gaps.

Rorschach Inkblot Test

A classic projective assessment consisting of bilateral, symmetrical inkblots that participants interpret to reveal underlying perceptual tendencies, psychological organization, and unconscious material.

Thematic Apperception Test (TAT)

A projective measure in which respondents compose open-ended stories about ambiguous interpersonal scenes, allowing clinicians to infer implicit relationship themes, motivational needs, and conflict dynamics.

Self-Report Inventories

Standardized questionnaires (e.g., Likert rating scales or True/False items) where individuals describe their own traits, assuming respondents possess self-awareness and answer honestly.

Social Desirability Bias

A systematic response bias in self-report assessment where respondents alter answers to present themselves in an overly favorable, culturally approved manner rather than reporting truthfully.

Minnesota Multiphasic Personality Inventory (MMPI)

A widely used clinical self-report inventory consisting of $567$ True/False items structured into $10$ clinical scales and built-in validity scales (L - Lie, F - Infrequency, K - Correction) to detect dishonesty and defensive responding.

Personology

Henry Murray's idiographic approach to studying whole human lives across the entire lifespan by integrating psychoanalysis, biology, literature, personal documents, and environmental press.

Life History Assessment

An in-depth, qualitative method of personality assessment that builds a holistic narrative of an individual using biographical interviews, creative works, letters, journals, and informant reports.

Electronically Activated Recorder (EAR)

A naturalistic acoustic methodology developed by Mehl and Pennebaker that intermittently samples ambient audio for $30\text{--}50\text{ seconds}$ every $12\text{--}15\text{ minutes}$ to observe real-world daily behavior objectively.