Does the ‘maturity principle’ hold for social, emotional, and behavioral skills? A study on age differences from 18 to 65

The maturity principle posits that socially desirable personality traits, such as agreeableness, conscientiousness and emotional stability tend to increase across adulthood. This study examined whether this principle extends to social, emotional, and behavioral (SEB) skills by investigating age differences in a representative sample of N = 940 German adults (age range: 18-65, mean age = 43, SD = 14, 50 % female) using moderated non-linear factor analysis models and comparing them to age differences in Big Five traits in a demographically comparable sample. Additionally, we explored age-specific associations between SEB skills and life quality, measured by life satisfaction and self-rated health. Contrary to the widely accepted maturity principle, we found few corresponding age differences in SEB skills, whereas the expected age-related patterns were evident in Big Five traits. These results remained consistent regardless of the level of measurement invariance. Some skills showed lower mean levels in older adults, and skill variances differed with age. In conclusion, these findings suggest that the maturity principle known from the Big Five literature does not fully generalize to SEB skills. This cross-sectional study lays the groundwork for future longitudinal research on SEB skills and highlights the importance of considering individuals within context.Keywords: age differences, life satisfaction, maturity principle, SEB skills, self-rated health