Personality

What is personality?

Personality refers to characteristic patterns of thought, feeling and behavior through which people differ. Traits summarize tendencies; they do not imply that someone behaves identically in every situation.

Fleeson's (2001) experience-sampling studies collected repeated descriptions of current behavior over two to three weeks. People varied considerably between occasions. He also randomly split each person's reports into two sets: people with higher average levels in one set tended to have higher averages in the other. This checks consistency across sets of observations, not whether traits remain unchanged years later. Someone can have quiet and outgoing moments yet be more outgoing on average than someone else.

Can personality change?

Changes in your usual tendencies over years are different from changes in your mood or behavior during one day. A meta-analysis of longitudinal studies combined research that followed the same people over time and found average trait changes across adulthood. This is mean-level change: a change in a group's average score. It does not mean that every person changes by the same amount.

There is also a separate question about relative position, called rank-order stability. Imagine two people who both become more organized over several years, while the one who started out more organized remains ahead. Their levels have changed, but their order has not. That hypothetical example explains why relative consistency can coexist with change. Neither a stable ranking nor an average increase shows how quickly a particular person could change through deliberate effort; that requires evidence about the effort itself.

A 2022 meta-analysis by Bleidorn and colleagues examined both relative position and average level over time. Rank-order stability increased through early life and largely leveled off in young adulthood, alongside changes in average trait levels. In practical terms, people became more consistent in their position relative to others without all change coming to an end.

For a fuller explanation of stability and change, see Can Personality Change?

Personality theories

Different theories describe different aspects of personality. OpenStax's overview of personality outlines several major approaches:

Trait theory: Describes dimensions such as the Big Five: openness, conscientiousness, extraversion, agreeableness, and neuroticism.
Psychoanalytic theory: Freud's account emphasizes unconscious conflict and early experience.
Humanistic theory: Maslow and Rogers emphasize personal growth and self-actualization.
Social-cognitive theory: Bandura emphasizes learning and interactions among beliefs, behavior, and environment.

Type systems, such as the Myers-Briggs Type Indicator (MBTI), put people into categories, while trait measures describe differences by degree. A type description might call someone an introvert; a trait score asks how introverted they are compared with other people. These approaches make different claims, and describing a person in one way does not establish that its underlying theory is correct. Evidence for a range of differences is not automatically evidence for separate kinds of people.

Openness, conscientiousness, extraversion, agreeableness and neuroticism each appear on a lower-to-higher continuum. — People differ in how strongly these traits show up across situations. The illustration shows the dimensions, without assigning anyone a score or type.

Personality assessment

Questionnaires, observations, and other assessments differ in what they measure and how well they support a particular use. A useful interpretation specifies the trait, measurement and context, instead of treating a personality label as a complete explanation or a fixed prediction of one person's behavior.

From a trait to a test result

The model and the questionnaire do different jobs. The Big Five organizes broad traits; an instrument such as the IPIP-NEO-120 uses a particular set of questions to estimate them. HEXACO organizes personality into six dimensions with some different trait content. Sharing a familiar trait name does not make scores from different instruments interchangeable.

Suppose a report describes you as low in extraversion. Before deciding what that means for your life, ask what the questionnaire measured, who supplied the comparison scores, and which part of extraversion the description concerns. Enjoying a quiet lunch with a friend and disliking a large party can coexist. The useful question is what kind of social activity suits you, not whether a label permits you to have a social life.

Test norms and percentiles explain the comparison behind a result. The guide to evaluating personality tests shows how to check the evidence before making more of a score than it can support.