Personality Traits and Inventories

Personality Traits and the Inventories That Measure Them

This section covers the definition of personality traits, their distinction from other psychological characteristics, the debate surrounding their existence, a review of structured personality inventories, and strategies for personality inventory construction.

Defining Personality Traits

Ashton's conceptual definition of a personality trait:

A personality trait reflects differences among individuals in their typical tendency to behave, think, or feel in some conceptually related ways across a variety of relevant situations and over a considerable period.

Key Elements of the Definition

  1. Difference Among Individuals: Personality descriptions are comparative. Traits differentiate people; characteristics everyone shares are irrelevant.

  2. Typical Tendency: Personality indicates the likelihood of specific behaviors, thoughts, or feelings. For instance, extroversion suggests a higher probability of attending parties and enjoying social interactions, but it doesn't guarantee it in every situation.

  3. Conceptually Related Ways: Behaviors linked to a trait share a common psychological element. For example, neuroticism encompasses selfishness, fearfulness, and insecurity, potentially related to biological differences.

  4. Consistency Across Situations: Traits should manifest across various relevant settings. An extroverted person should exhibit extroverted behaviors at school, social events, and in other diverse contexts.

  5. Stability Over Time: Personality traits are generally stable. Agreeableness observed today is expected to persist next week, next year, and even several years into the future.

Personality Traits vs. Other Psychological Characteristics

Traits are distinct from mental abilities and attitudes. While personality may predict attitudes (e.g., friendly people having positive attitudes towards strangers), they are separate constructs.

The Existence and Controversies of Personality Traits

Historical Criticism
  • Hartshorne and May Study: Investigated moral character in 11,000 children, looking at altruism, self-control, and honesty, and found low consistency (correlation of 0.2) between behaviors.
  • Walter Mischel's Situationism: Argued that behavior depends more on the specific situation than on personality. For example, conscientiousness in crossing a street depends on the presence of a red light and police.
Rebuttal to Criticism
  • Aggregation of Behaviors: Research needs to aggregate behaviors across different situations and times to get an accurate description of personality. Jackson and Paunonen found correlations of around 0.5 when aggregating behaviors.
  • Personality influences the likelihood of behaviors across time and situations, not single behaviors in specific instances.
  • Mischel's research highlighted the interaction between personality and situations. Personality plays a more significant role in open situations with more freedom.

Structured Personality Inventories

  • California Psychological Inventory (CPI): A large, 400-item questionnaire based on the Minnesota Multiphasic Personality Inventory (MMPI), aimed to measure mental illness.
  • Eysenck Personality Questionnaire (EPQ): A biological-based model measuring neuroticism, extroversion, and psychoticism.
  • Temperament and Character Inventory (TCI): Another biologically based model developed by Cloninger and colleagues.
  • Myers-Briggs Type Indicator (MBTI): Classifies people into types. It is considered not scientifically sound due to crude measures, limited reliability and validity. Classifying someone as an extrovert doesn't give an indication of how highly this person is extroverted, doesn't give any indication about what other characteristics this person has.

The Big Five Framework

Comprises five major dimensions:

  • Neuroticism
  • Extroversion
  • Openness to Experience
  • Agreeableness
  • Conscientiousness

Measures:

  • Big Five Inventory (BFI): 44 items
  • NEO Five-Factor Inventory (NEO-FFI): 60 items
  • NEO Personality Inventory Revised (NEO PI-R): 240 items

The acronym OCEAN (Openness, Conscientiousness, Extroversion, Agreeableness, Neuroticism) serves as a memory aid.

The HEXACO Model

Developed by Lee and Ashton, this model contains six dimensions:

  • Honesty-Humility (H)
  • Emotionality (E)
  • Extraversion (X)
  • Agreeableness vs. Anger (A)
  • Conscientiousness (C)
  • Openness to Experience (O)

Different versions are available with 100 or 60 items.

The H factor (Honesty-Humility) was introduced as a missing element in the Big Five model.

Strategies for Personality Inventory Construction

  1. Empirical Strategy: Collects items based on empirical relationships with the trait of interest. For example, items like "I like to eat red meat" might be used to evaluate masculinity.
  2. Factor Analytic Strategy: Uses factor analysis to identify groups of items that measure different traits.
  3. Rational Strategy: Involves writing items based on theory, experience, and research that describe the trait being measured. An example is the Multidimensional Perfectionism Scale by Hewitt and Flett.

Factor Analytic strategy is the biggest strategy used nowadays.

Summary of Key Points

  • Personality traits require a clear conceptual definition.
  • Single behaviors poorly predict personality; aggregation across situations is necessary.
  • Widely used personality inventories include the EPQ, Big Five questionnaires (BFI, NEO PI), and the HEXACO.
  • Three main strategies for personality inventory construction are the empirical, factor analytic, and rational strategies.