Lifespan trends in sociability: Measurement invariance and mean-level differences in ages 3 to 86 years

Although sociability is a fundamental dimension of temperament and personality, few studies have examined it over the lifespan. In this study, sociability was measured across ages 3 to 86 years after assessing for measurement invariance through the multigroup confirmatory factor framework and the more recent alignment method to ensure meaningful differences were assessed between different age groups. Using a repeated cross-sectional design, separate adult (N = 1366, ages 17–86 years) and child/adolescent (N = 543, ages 3–16 years) datasets were created to improve research validity across two different but comparable sociability scales. The findings indicated that there was measurement invariance across adult age groups, but not among child/adolescent age groups. Average levels of sociability followed a significant nonlinear trend (quadratic) across the adult lifespan. Measurement invariance was found across sex for both adult and child/adolescent samples. In adults, females had higher average levels of sociability than males, whereas in children/adolescents, females and males did not differ in mean-levels of sociability. We discuss potential explanations for the quadratic nature of sociability across the adult lifespan, the theoretical implications of these results to understanding personality development, and the methodological issues encountered in studying lifespan differences in sociability from early childhood to senescence.