Cognitive and neural foundations of perceptual biases for the self and social groups

The notion of the self as distinct from other people is fundamental to the study of human psychology. Closely tied to this sense of self is the profound importance of belonging to social groups. The cognitive prioritisation of self- and ingroup-related information, known as self-bias and ingroup-bias, occurs across a multitude of cognitive domains. Although adaptively beneficial, biases arising from social categorisation are the source of prejudiced attitudes, discriminatory behaviours and intergroup conflict. Several studies have demonstrated enhanced response times and accuracy performance in perceptual matching for self and ingroup stimuli compared to others and outgroups. However, the cognitive and neural mechanisms underlying these effects are relatively unexplored. The present thesis examines five core outstanding research questions: 1. What is the relationship between perceptual prioritisation for the self and social ingroups? 2. How does social context modulate ingroup-bias? 3. How quickly does group affiliation affect early perceptual processing? 4. Do trait differences underlie the strength of perceptual prioritisation for the self and social groups? 5. What are the commonalities and distinctions in the neural regions that underpin biases for the self and social ingroups? Broadly, the findings of this thesis suggest that: 1. There is an overlap in the representation of stimuli associated with the self and ingroups but the performance advantages are likely to be driven by partly distinct processes. 2. Perceptual biases for ingroups are robust across differing social contexts. 3. Social categorisation quickly enhances low-level perceptual processing even when this categorisation is novel and random. 4. There is no evidence to suggest that individual trait differences in group identification or self-concept underpin the perceptual biases. 5. Cognitive prioritisation for the self and ingroups are supported at least in part by distinct neural mechanisms. Together, these findings provide a novel perspective on the relations between self and ingroup representation in brain and behaviour.