Browsing by Author "Kretsch, Natalie Sara"
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Item Pubertal development and adolescent risk-taking : understanding individual differences(2016-08) Kretsch, Natalie Sara; Harden, Kathryn Paige; Cavanagh, Shannon E; Fromme, Kim; Josephs, Robert A; Yeager, David SThis set of projects focused on individual differences—specifically, how variation in the timing, context, and perception of this universal milestone might contribute to individual differences in risky behavior. Study 1 looked at testosterone as a potential endophenotype for substance use in adolescence. Combining self-report, hormonal, and behavioral measures, this study used a twin design to test the hypothesis that testosterone mediated genetic risk for substance use via its effect on reward seeking. The primary hypothesis was not supported, as there were no phenotypic associations between testosterone, reward seeking, and initiation of substance use. Study 2 focused on girls’ perceived pubertal timing in the context of their peer group, testing whether peer delinquency moderated the association between pubertal timing and delinquency. A twin comparison design was used to control for unmeasured between-family differences (family-level genetic and environmental selection effects) that would affect both peer and individual delinquency. Pubertal timing moderated the quasi-causal association between peer and individual delinquency: girls with earlier perceived pubertal timing were more similar to their nominated friends in delinquency. This interaction was only found for relative pubertal timing (asking girls to compare their development to their peers) and not for age-standardized ratings of body changes or for age at menarche. Study 3 examined whether pubertal timing reported by one’s friends and schoolmates related to perceived pubertal timing. Results showed gender differences: boys appeared similar to their peers in perceived body changes and girls appeared similar to peers in perceived relative pubertal timing. Collectively, these 3 studies highlight complexity inherent in studying sources of individual differences at a stage when numerous changes—biological, psychological, social—are underway. Understanding the extent to which these concurrent changes may or may not interact is an important step toward identifying factors that make some children prone to risk behavior.Item Pubertal timing and peer influence on risky decision-making(2012-12) Kretsch, Natalie Sara; Harden, Kathryn Paige; Fromme, KimAdolescents engage in more risky behavior when they are with peers and show heightened susceptibility to peer influence relative to children and adults. Recent experimental studies suggest that peer influence on adolescent risk-taking may be mediated by activity in reward-related regions of the brain (Gardner & Steinberg, 2005; Chein et al., 2011). Because reward-related regions are modified by the hormonal changes of puberty, it is possible that the heightened influence of peers on adolescent risk-taking is more closely linked to pubertal development than chronological age. The current study examined whether the effect of peers on risk-taking was moderated by pubertal status. Participants (62 youth, ages 11-16) completed a performance-based measure of risky decision-making, once alone and once in the presence of two peers. Pubertal timing was assessed using self-report. Adolescents made riskier decisions in the presence of peers, and more advanced pubertal development predicted greater risky decision-making, controlling for chronological age. However, the relationship between pubertal timing and risk-taking was only apparent when adolescents completed the task alone. The effect of peer presence on risky decision-making was attenuated for adolescents with more advanced pubertal development. These findings suggest that the presence of peers may override biologically-based individual differences in propensity for risk-taking.