Using within-person change in three large panel studies to estimate personality age trajectories

Area of Science:

• Psychology
• Developmental Psychology
• Personality Science

Background:

• Personality maturation is widely supported, but findings on its continuation in old age and effect sizes are inconsistent.
• Methodological issues, including conflating within-person and between-person changes and item-level heterogeneity, may explain inconsistent findings.

Purpose of the Study:

• To investigate age trends in the Big Five personality traits using a within-person approach.
• To examine personality development at both the trait score and individual item levels.
• To clarify inconsistencies in previous personality maturation research.

Main Methods:

• Analysis of large-scale longitudinal panel data from Australia, Germany, and the Netherlands (N = 48,264).
• Application of a fixed-effects approach to exclusively analyze within-person changes over time.
• Examination of age trends for both aggregated Big Five trait scores and individual questionnaire items.

Main Results:

• Moderate to large personality maturation effects were observed, particularly at younger ages.
• Personality maturation continued consistently for Neuroticism in older age.
• Mixed evidence for continued maturation in Conscientiousness and Agreeableness was found; individual items displayed divergent age trends.

Conclusions:

• The study confirms personality maturation, especially in younger individuals, and its continued progression for Neuroticism into older age.
• Divergent age trends at the item level highlight the importance of item-specific analysis in personality development research.
• The findings offer a methodological explanation for variability in previous personality development studies.