The development of social and executive functions in late adolescence and early adulthood

Executive functions and social cognition develop throughout childhood into adolescence and early adulthood (Blakemore & Choudhury, 2006). These functions are associated with frontal networks showing protracted maturation into early adulthood (Lebel, Walker, Leemans, Phillips & Beaulieu, 2008). Executive function and social cognition studies have previously focused on childhood (Pennequin, Sorel & Fontaine, 2010), adolescence (Magar, Phillips & Hosie, 2010) or broad age ranges in adulthood (Dziobek et al., 2006). This thesis reports executive function, social cognition, IQ and mood state data in a sequential design with 98 participants aged 17 (Younger group), 18 (Middle group) and 19 years (Older group) at Time 1. Findings indicate non-linear development, with a trough in ability at age 18, on strategy generation and concept formation, assessed with Letter Fluency and Sorting Tests from the Delis Kaplan Executive Function System (Delis, Kaplan & Kramer, 2001). There were no group differences on Time 1 social cognition task scores. Fifty eight participants were tested at Time 2 (interval between testing M = 14.81 months, SD = 4.01). Again, the Younger group scored significantly higher than the Middle group on strategy generation at Time 2 suggesting that group differences may represent sample characteristics rather than age related change. There were no group differences in concept formation at Time 2, indicating that non-linear development is specific to age 18 in the present sample. Inhibition, rule detection, strategy generation, planning and emotion recognition in dynamic stimuli showed progressively better longitudinal development. IQ, Age, Depression, Anxiety and executive function scores (rule detection, strategy generation, inhibition and planning) predicted performance on social cognition tasks assessing emotion recognition in visual static (Reading the Mind in the Eyes Test; Baron-Cohen et al., 2001), auditory (Reading the Mind in the Voice Test; Golan, Baron-Cohen Hill & Rutherford, 2007), dynamic visual and auditory stimuli (Movie for the Assessment of Social Cognition; Dziobek et al., 2006) and selfreport empathy (Interpersonal Reactivity Index; Davies, 1983). Overall, results indicate linear and non-linear development of functions in late adolescence and early adulthood. Clinical and educational implications of these findings are discussed.