Age and individual differences in reinforcement learning: A behavioural and electrophysiological study

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Adaptive behaviours rely on the ability to use performance feedback to guide behaviour. Both positive and negative feedback are important for improving performance, signaling either a continuation or an adjustment of the current behaviour and for the efficient deployment of attentional resources. Performance monitoring is particularly important during childhood and adolescence since they are constantly faced with new, often challenging, learning experiences in social and educational settings. Evidence suggests that there is protracted development of the brain reward system and these immaturities may have profound effects on how individuals evaluate performance feedback. Event-related potentials (ERPs) recorded from the scalp can be used to examine performance monitoring and the neural mechanism underlying it. Few studies have systematically examined ERP responses to performance feedback across development. Importantly, performance monitoring has been traditionally investigated in response to monetary feedback. The most salient feedback signals may, however, be social in nature, and negative social evaluation is likely a potent signal leading to strong brain reward responses. Inconsistencies in methodology and results raise the possibility that differences in how individuals respond to negative and positive feedback may depend, in part, on motivational factors such as individual differences in sensitivity to punishment and reward as found with internalizing and externalizing traits, respectively. The primary goal of the proposed study is to address existing inconsistencies and systematically examine age differences in responses to positive and negative performance feedback (both monetary and social) using an ERP approach. In light of the drastic increase in mood and behavioural disorders from childhood to adolescence, it may be especially important to identify early neural markers of reward-related dysfunction that might precede the emergence of a full-threshold disorder in adolescence and adulthood. Reward-related ERPs may be ideal biomarkers for studying changes in reward sensitivity and internalizing/externalizing traits that emerge as children transition through puberty. Hence, the secondary goal of this study iss to examine the association between internalizing/externalizing traits in relation to a putative neural marker of diminished responsiveness to reward and punishment performance feedback from late childhood to young adulthood. Reaching a clearer understanding of the functional significance of reinforcement learning error related signals is crucial if their modulation were to be interpreted as biomarkers or risk indicators. This is an important first step toward the eventual goal of linking a neural marker seen in childhood and adolescence to the development of more severe internalizing/externalizing problems in adulthood.