Decision making and social neurocognition during adolescence.

Adolescents show a tendency to engage in risky activities, such as dangerous driving and unsafe sex. This has led to the suggestion that adolescents are poor decision-makers, and are risk-seeking in general. The first two chapters of this thesis describe studies investigating adolescent decision-making using probabilistic decision-making tasks. In Chapter 2, the tendency to seek risk, and the ability to integrate probability and reward information to make an optimal decision, is investigated in child, adolescent and adult participants. The emotional response to outcomes was also investigated. In Chapter 3, a computational approach is adopted to investigate the role of positive and negative performance feedback (wins and losses) in a probabilistic decision-making task in adolescents and in adults. The role of social-emotional factors in decision-making was also investigated. Adolescence is characterised by social and emotional development, as well as development in the functional brain correlates of social-emotional processing. Therefore, Chapters 4 to 6 focus on adolescent social-emotional processing using behavioural and functional neuroimaging methods. In Chapter 4, results are presented from a study of self-reported social and basic emotions across adolescence, where social emotions (e.g. embarrassment) are defined as emotions that require an awareness of others’ mental states (e.g. emotions, opinions, desires). In Chapter 5, the neural correlates of social and basic emotion processing are investigated in adolescents and in adults, using functional magnetic resonance imaging (fMRI). Finally, in Chapter 6, these fMRI data are reanalysed using a technique known as psycho-physiological interaction (PPI) analysis, to look at age-associated changes in effective connectivity. Results are discussed in the context of social cognition and neuroanatomical development.