Trajectories of big five personality traits: A coordinated analysis of 16 longitudinal samples
Eileen K Graham, Sara J Weston, Denis Gerstorf, Tomiko B Yoneda, Tom Booth, Christopher R Beam, Andrew J Petkus, Johanna Drewelies, Andrew N Hall, Emily D Bastarache
*European Journal of Personality*
Abstract
This study assessed change in self-reported Big Five personality traits. We conducted a coordinated integrative data analysis using data from 16 longitudinal samples, comprising a total sample of over 60 000 participants. We coordinated models across multiple datasets and fit identical multi-level growth models to assess and compare the extent of trait change over time. Quadratic change was assessed in a subset of samples with four or more measurement occasions. Across studies, the linear trajectory models revealed declines in conscientiousness, extraversion, and openness. Non-linear models suggested late-life increases in neuroticism. Meta-analytic summaries indicated that the fixed effects of personality change are somewhat heterogeneous and that the variability in trait change is partially explained by sample age, country of origin, and personality measurement method. We also found mixed evidence for predictors of change, specifically for sex and baseline age. This study demonstrates the importance of coordinated conceptual replications for accelerating the accumulation of robust and reliable findings in the lifespan developmental psychological sciences.
Why we asked
For a long time, the textbook view was that personality settles down early in adulthood and stays put. More recent work says traits do change, and that people change at different rates, but the studies disagree about how. Most of them also rely on a single dataset. If a study of retirees in Berlin and a study of veterans in Boston give different answers, it is hard to tell whether the people differ or the analyses do. We wanted to know how the Big Five traits change in midlife and older adulthood, and whether the answer holds up across many samples.
What we did
We used a coordinated analysis. Before we looked for data, we wrote the analysis scripts. We then found 16 longitudinal studies, with more than 60,000 participants in all, that had measured personality at least three times, and we fit the same multilevel growth model in each one. Finally, we combined the estimates meta-analytically. In other words, we ran 16 close replications of one analysis rather than pooling everything into one dataset, which let us see how much the answers differed from sample to sample.
What we found
On average, extraversion and openness declined (b = -0.09 per decade for each, on a 10-point scale), and conscientiousness declined a little less (b = -0.05). Neuroticism followed a U-shape: it fell through most of adulthood and rose again in later life. Agreeableness showed no consistent pattern (b = 0.02, 95% CI [-0.02, 0.07]). These are small changes, roughly a tenth of a point per decade, though they add up over a long life.
Most samples also showed that people differ in how much they change. The samples disagreed with one another quite a bit, and the measurement scale, the average age of the sample, and the country explained only part of that. Sex was associated with very little, apart from slightly steeper declines in neuroticism among women. Baseline age was associated with different trajectories for every trait. For conscientiousness, for example, declines were most evident among people who were over 60 when they started.
What it means
The declines fit theories in which older adults drop the behaviors that work and family once demanded. We did not test that explanation, so it remains speculation. With only 16 samples, we also had limited power to explain why they differed.
Replicating an analysis across many datasets shows how much a finding depends on the sample.