Social Selves and Social Others in Adolescent Development

The aim of the studies reported in this thesis was to deepen our understanding of how the specific social conditions under which an individual develops influences their psychosocial adjustment. Adolescence is a sensitive window for the development of cognitive and affective functions and schemata, and all but one (Chapter 6) of the presented studies were therefore conducted with 12-15 year-olds. During adolescence, the salience of peer-related social reward undergoes a dramatic increase, and autonomy becomes a high priority in their familial relationships. Adolescents consequently “socially reorient,” from family toward peers. Unlike familial relationships, peer relationships are ‘voluntary’, and therefore conditional. Adolescents must learn to navigate unstated conditions, adjusting their behaviour to differing, and often conflicting, sets of expectations with multiple different individuals across a number of contexts. In turning to peers to replace parents as their primary social supports, adolescents may often find themselves in a parallel struggle to establish autonomy, not (only) from parents but from their friends and peer group. Indeed, the surge in peer-related social reward sensitivity may lead adolescents to perceive risks to their social connections and/or status as far outweighing other considerations. Since identities, like social behaviours, are often shaped by relationships and how we believe our relationship partners perceive us, this supports the developmental task of establishing a flexible, stable and unified identity. Combined with the increased need for context-sensitive social behaviour, this requires adolescents to develop multiple role-related selves. Drawing on Self-Determination Theory (SDT), the Adaptive Calibration Model (ACM), and related scholarship, this thesis will argue that adolescence can be understood as a period in which long-term adaptation to one’s sociocultural context is accomplished in part by canalising a variety of self- consistent, context-sensitive behavioural ‘modes’, which may be represented as facets of the self, and that adolescent-onset internalising disorders can be understood as dysregulation of this system of adaptive identity.