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

The maturity principle suggests that socially desirable personality traits, such as agreeableness, conscientiousness and emotional stability increase across adulthood. This study examined whether this principle extends to social, emotional, and behavioral (SEB) skills by investigating age differences in SEB skills using moderated non-linear factor analysis models in a representative sample of N = 940 German adults (age range: 18-65, mean age = 43, SD = 14, 50 % female). Additionally, age-specific associations between SEB skills and life quality, measured by life satisfaction and self-rated health, were explored. Contrary to the widely accepted maturity principle, few corresponding age differences were found in SEB skills. These results remained consistent regardless of the level of measurement invariance. In fact, some skills showed even lower mean levels in older adults, and skill variances differed across age. These findings challenge application of the maturity principle to SEB skills and its use as a general developmental rule. Moreover, this study underscores the need for research that more explicitly considers individuals within their contexts for a better understanding of skill development.Keywords: age differences, maturity principle, SEB skills, health, life satisfaction