Do People Become More Alike Across the Lifespan? A Meta-Analysis of Changes in the Variability of Personality Traits

Do people become more different or more alike in their personality across the lifespan? Despite the theoretical and practical relevance of this question, relatively little is known about how individual differences in personality traits – typically assessed as their variance – develop across the lifespan. Existing meta-analyses on personality development have found that the mean-levels and rank-orders of personality traits change over time but they neglected possible changes in the variability of personality traits. The present meta-analysis aimed to fill this gap in the literature by integrating research from 362 longitudinal studies (total N = 344,270). Across traits, we found a remarkable stability of personality variability, indicating that people neither get more different nor more alike across time and age. The only deviations from this pattern were found in childhood, suggesting that the variability of extraversion, neuroticism, and openness decreases in the first years of life (ages 1 to 4) and that the variability of neuroticism increases in late childhood (ages 5 to 13). These findings were robust across various publication, sample, and assessment characteristics. Our results challenge contemporary theories of personality development that imply decreases or increases in the variability of personality traits. Furthermore, the high stability of personality variability has important implications for personality science as it influences statistical modeling and is relevant for the prediction of life outcomes.