Does Personality Change Over Time?

February 7, 2018 Richard Justenhoven
personality over time

The consistency of personality as we get older

We’re often asked if personality changes over time. Not just, but especially by those just starting to think about introducing personality assessments at work. Once they assess and map out a personality profile as a graduate enters the business, does he or she fundamentally have the same personality when getting their long service award?

We were interested to hear of a research study carried out by Eileen Graham and her team in which she compared and combined data from 14 published longitudinal studies which, together, look at nearly 50,000 participants. Although at the time of the initial study the ‘personality’ element was not necessarily considered, personality data had been collected, in some cases, over a number of decades from the same cohort.

Her paper suggests that when combining the data from all the studies, four of the five main personality traits showed statistically significant change, on average, through life. And that these trait scores declined by around 1-2% each decade.

It means that participants became over their lifetime:

  • more emotionally stable – other than an increase at the very end of life;
  • less outgoing;
  • less open-minded;
  • less orderly and self-disciplined.

The exception to this was the trait of Agreeableness which was found to change in each study but in different directions and thus, when aggregated suggested that it didn’t shift over time.

What does this mean for assessing personality at work?

This study is, without a doubt, of great interest. In a world where it is easy to carry out the re-assessment of sample groups within a relatively short period of time and so much harder to follow the same group of people and retest them at significant time intervals, this report offers an attempt to do that.

But it is worth noting that there was some biases which no doubt had an impact. For example, the team included older aged people in the samples but when looking at only younger participants (of working age) a different picture emerges. There seems to be an increase over time of the traits of Conscientiousness, Extraversion and Openness – and this supports the theory of the ‘maturity principle’ (that we tend to gradually mature our personalities as we adapt to the growing challenges and responsibilities of life, work and family).

Personality and behavioural assessments are widely used in many selection and development practices when looking for specific behaviours needed for a job or role. We believe that, as long as the assessment itself is robust and proven to be reliable, valid and objective, it is possible to create an accurate view of a person’s personality that will be quite stable over a number of years – longer than he or she will be in any single role!


Awaiting peer review and pre-published at the PsyArXiv repository.

About the Author

Richard Justenhoven

Richard Justenhoven is the product development director within Aon's Assessment Solutions. A leading organizational psychologist, Richard is an acknowledged expert in the design, implementation and evaluation of online assessments and a sought after speaker about such topics.

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