Personality: What Actually Holds Up

Personality research has one well-supported model and one enormously popular one, and they are not the same model. The Big Five emerged from decades of data and replicates across cultures; Myers-Briggs sells better. [goldberg-1990-bigfive] This guide covers what traits actually predict, why treating them as types loses most of the information, and the finding that surprises people most: personality changes.

Dimensions, not types

The single most important idea here is that traits are continuous. Almost everybody sits somewhere in the middle of each dimension, and the distribution is a hump rather than two camps.

Sorting people into types throws that away. Someone at 51 per cent on a dimension and someone at 49 per cent are nearly identical and end up in different boxes, while the person at 51 is grouped with someone at 99. That is not a subtle statistical complaint; it is the reason type-based instruments give unstable results.

	Big Five	Myers-Briggs
Structure	Five continuous dimensions	Sixteen discrete types
Origin	Found in data, across languages	Derived from Jungian theory
Retest stability	Good	Poor; many people change type on retaking
Predicts outcomes	Yes, across work, health and relationships	Weakly at best
Used in research	Standard	Rare

The five, and what each one does

Openness to experience covers curiosity, aesthetic interest and comfort with the unfamiliar. It predicts creative achievement and choice of field more than performance within one.

Conscientiousness covers organisation, persistence and reliability. It is the quiet winner of this literature: Barrick and Mount found it predicted job performance across essentially every occupational group studied, which almost nothing else does. [barrick-1991-performance] It also predicts longevity.

Extraversion covers sociability and positive emotionality. It predicts how much positive emotion someone reports, and it does not settle whether they are happy overall, which is a distinction people routinely collapse.

Agreeableness covers warmth, trust and cooperation. High agreeableness is good for relationships and, awkwardly, is associated with lower earnings.

Neuroticism covers the tendency to experience negative emotion. It is the trait most relevant to this site, being associated with higher risk of anxiety and depression, and it is also the one that most reliably declines with age and with treatment.

Personality changes

The assumption that personality is fixed by early adulthood is wrong, and the evidence against it is substantial. Roberts and colleagues pooled longitudinal studies and found systematic mean-level change continuing well into middle and older age. [roberts-2006-change]

The direction is consistent enough to have a name. People tend to become more conscientious, more agreeable and less neurotic as they get older, sometimes called the maturity principle. This happens without anybody trying.

Deliberate change also appears possible. Work reviewed by Soto and Jackson suggests people who want to change a trait and take repeated action toward it can shift it measurably over months. [soto-2021-change] The mechanism is unglamorous: acting differently, repeatedly, until it stops requiring a decision.

Where change comes from across adulthood Illustrative

Ordinary maturation with age 45%
Life roles: work, partnership, parenting 30%
Deliberate effort and therapy 15%
Stable across the period 10%

A schematic of the contributions described in the personality development literature. Proportions illustrate the relative picture rather than reporting measured variance.

Where this touches mental health

Neuroticism is the connection, and it is worth being careful about the direction. High neuroticism is associated with greater risk of anxiety and depression, which does not mean it is those conditions or that having it means you will develop them.

It also moves. Neuroticism declines with age on average, and it declines with successful treatment for anxiety and depression, which suggests some of what is measured as a trait is closer to a current state than the word trait implies.

Personality disorder is a different topic, describing patterns rigid and pervasive enough to cause substantial impairment. Our pillars on borderline personality disorder and narcissism cover the two most discussed, and the second is largely about how loosely the word gets used.

Traits or something treatable?

Personality traits are not problems. This checks for the pattern where something treatable is being filed as just how I am.

I avoid social situations because of what people might think, not because I prefer quiet
Worry runs most days regardless of what is actually happening
I have stopped doing things I used to enjoy
The pattern got noticeably worse in the last year, rather than being lifelong
It costs me work, relationships or sleep
People who know me well have said I seem different

0 of 6 ticked

What to do with a test result

Treat it as a description of tendencies, checkable against your own behaviour, rather than as a fact about you. A result that does not match what you actually do is a result to doubt.

Be suspicious of anything that arrives with career advice, compatibility ratings or a flattering identity. Descriptions general enough to fit almost anyone feel remarkably accurate, which is why the effect has a name and why the most engaging instruments are frequently the least valid.

And treat a score as a starting position rather than a ceiling, given how much the longitudinal evidence says these move.

When to speak to someone

See a doctor if a pattern you have been filing under personality has changed recently, is costing you work, sleep or relationships, or has narrowed what you are willing to do. That combination points at something treatable rather than something fixed.

Social anxiety in particular is very often mistaken for introversion, and it responds well to treatment. Our guides to social anxiety versus introversion and social anxiety cover the distinction.

How MyFreud can help

The trait-or-state question is answered by whether something moves, and that is exactly what a single moment cannot tell you. Tracking mood over months shows whether what feels like a permanent characteristic is actually varying with sleep, season and circumstance.

Frequently asked questions

What are the Big Five personality traits?

Openness to experience, conscientiousness, extraversion, agreeableness and neuroticism, sometimes remembered as OCEAN. They emerged from the lexical hypothesis, the idea that whatever matters about personality will have ended up encoded in ordinary language, so researchers analysed the descriptive words people use about each other and found five broad clusters recurring. That origin is a strength rather than a weakness: the model was discovered in data rather than proposed by a theorist, and it replicates across cultures and languages reasonably well.

Is Myers-Briggs accurate?

It performs badly on the two things a psychological instrument has to do. Its test-retest reliability is poor, with a substantial proportion of people receiving a different type when retested weeks later, which is a serious problem for something presented as an identity. And it forces continuous traits into binary categories, so somebody just over the line on a dimension is grouped with people at the extreme and separated from someone almost identical to them. It remains popular because the descriptions are engaging, flattering and general enough to fit almost anyone, which is a well-documented effect rather than evidence of accuracy.

Does personality change?

Yes, more than most people expect. Roberts and colleagues pooled longitudinal studies and found systematic mean-level change continuing across adulthood, including into middle and older age: people tend to become more conscientious and agreeable and less neurotic as they get older, a pattern often called the maturity principle. Deliberate change is also possible, with evidence that people who want to change a trait and act on it can shift it measurably over months. What does not change much is your rank relative to other people, which is why change feels slower from inside than it is.

Which trait matters most?

Conscientiousness, for the widest range of outcomes people care about. It predicts job performance across essentially every occupation that has been studied, which is unusual for any single measure, and it also predicts longevity, partly through health behaviours and partly through routes that are still debated. Neuroticism is the trait most relevant to mental health, being associated with higher risk of anxiety and depression. Extraversion predicts positive emotion but not, contrary to popular belief, whether you are happy in any overall sense.

Is being introverted a problem?

No, and framing it as one is a category error worth resisting. Introversion is a normal position on a normal dimension and predicts different preferences rather than worse outcomes. What is sometimes mistaken for introversion is social anxiety, which is a different thing entirely: introversion is a preference for less social stimulation, while social anxiety is fear of judgement in social situations. An introvert who is not anxious is fine. Someone avoiding social contact out of fear has something treatable, and the distinction decides whether anything needs doing.

References

1.Goldberg LR ( 1990). An alternative "description of personality": the Big-Five factor structure. Journal of Personality and Social Psychology.

2.Roberts BW, Walton KE, Viechtbauer W ( 2006). Patterns of mean-level change in personality traits across the life course: a meta-analysis of longitudinal studies. Psychological Bulletin.

3.Barrick MR, Mount MK ( 1991). The Big Five personality dimensions and job performance: a meta-analysis. Personnel Psychology.

4.Soto CJ, Jackson JJ ( 2021). Personality development in adulthood. Annual Review of Psychology.