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UBC Theses and Dissertations

The neurobiological bases of infants’ sensitivity to sociomoral scenarios Tan, Enda


Human beings show a pervasive tendency to evaluate others based on their sociomoral behaviors. Recently, a growing literature demonstrates that even preverbal infants are sensitive to prosocial and antisocial interactions, suggesting that the rudimentary aspects of sociomoral evaluations may develop early in life (Ting et al., 2020). However, it remains unclear whether infants’ responses to sociomoral interactions are social in nature, and whether affective processes are involved when infants process sociomoral scenes. The current dissertation explores these questions by systematically examining infants’ real-time responses to helping and hindering interactions. In Chapter 1, I provide an overview of evidence for sensitivity to sociomoral scenarios in infancy and discuss how neurophysiological measures can shed light on the nature and mechanisms of this sensitivity. In Chapter 2, I examine how infants process sociomoral scenes by assessing infants’ eye-movement and pupillary responses to helping/hindering interactions using eye-tracking. Through a detailed analysis of infants’ visual attention and pupillary responses, I explore whether infants attend to socially relevant aspects of the displays, whether infants’ online looking behaviors predict social preferences, and whether infants show differential arousal responses to prosocial and antisocial scenarios. In Chapter 3, I examine infants’ neural responses to helping/hindering interactions using electroencephalography (EEG). By investigating whether helping/hindering scenarios and characters elicit differential responses in neural signatures of task-relevant mental processes, I explore whether helping/hindering interactions evoke approach-avoidance motivations and whether socially relevant neural processes are implicated when infants respond to prosocial/antisocial characters. Chapter 4 focuses on infants’ arousal/affective responses to sociomoral scenarios. Using facial electromyography (EMG), I explore whether infants show positive and negative facial responses when viewing helping/hindering scenarios. By assessing infants’ electrodermal activity (EDA) and pupillary responses, I examine whether infants’ arousal levels change in reaction to prosocial/antisocial interactions. Together, the results provide convergent evidence that infants’ responses to helping/hindering interactions are based on socially relevant processes, and that arousal/affective processes are implicated when infants respond to sociomoral scenarios. These findings provide a more holistic account of how different mental processes relate to infants’ sociomoral evaluations, and shed light on long-lasting debates about the nature and mechanisms of early sociomoral functioning.

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