Previous research has demonstrated that in-group favouritism occurs not only in higher-level judgments such as reward allocation, but also in low-level perceptual and attentional tasks. Recently, Moradi, Sui, Hewstone, and Humphreys (2015) found a novel effect of in-group bias on a simple perceptual matching task in which football fans responded more efficiently to stimuli newly associated with their own football team than stimuli associated with rival or neutral teams. This result is consistent with a robust self-bias effect in which individuals show a large performance advantage in responding to stimuli associated with the self over stimuli associated with a close friend or a stranger (Sui, He, & Humphreys, 2012). The present research utilised a perceptual matching paradigm to investigate the relations between self and in-group prioritisation amongst a sample of college rowers. Across two experiments, we demonstrated a reliable performance advantage for self and team stimuli. We also found a relationship between the self and team advantage in RT, and demonstrated an overlap in the perception of self- and team-associated shapes that was stronger in participants who reported a greater sense of group identity with their team. Further, we found no relation between the team bias and positive valence implicitly associated with the team, showing that the team bias effects are unlikely to be driven by emotional significance. The results are consistent with an overlap between self and in-group representation, which may provide evidence for a common process driving both self and in-group perceptual advantage effects.

According to the dual model, outgroup members can be dehumanized by being thought to possess uniquely and characteristically human traits to a lesser extent than ingroup members. However, previous research on this topic has tended to investigate the attribution of human traits that are socially desirable in nature such as warmth, civility and rationality. As a result, it has not yet been possible to determine whether this form of dehumanization is distinct from intergroup preference and stereotyping. We first establish that participants associate undesirable (e.g., corrupt, jealous) as well as desirable (e.g., open-minded, generous) traits with humans. We then go on to show that participants tend to attribute desirable human traits more strongly to ingroup members but undesirable human traits more strongly to outgroup members. This pattern holds across three different intergroup contexts for which dehumanization effects have previously been reported: political opponents, immigrants and criminals. Taken together, these studies cast doubt on the claim that a trait-based account of representing others as ‘less human’ holds value in the study of intergroup bias.

Biases to favour self-related information over information related to other people have been demonstrated across a range of both high- and low-level tasks, but it is unclear whether these tasks 'tap' the same types of self representation. Here we assess results from two patients with damage primarily to (i) left ventro-medial prefrontal (vmPFC) cortex and the insula (patient SC), and (ii) temporo-parietal (TP) cortex (patient RR). We report evidence from both low-level perceptual matching tasks and episodic memory showing that SC has a hypoself bias across the tasks. RR in contrast had a hyperself bias confined to perceptual matching. Both patients also showed hypobias effects for reward. We argue that the different brain lesions compromise (i) the use of a core self-representation which modulates both perceptual and memorial levels of processing (the vmPFC), and (ii) attentional responses to social cues (the TP cortex), and, furthermore, these effects can dissociate from those of reward and general effects of brain lesion and/or impaired executive control. We suggest that the vmPFC is critical for access to a core self-representation while TP damage can reduce top-down control of attention to salient stimuli and exaggerates the effects of strong (self-related) attentional signals.

Cognitive biases shape our perception of the world and our interactions with other people. Information related to the self and our social ingroups is prioritised for cognitive processing and can therefore form some of these key biases. However, ingroup biases may be elicited not only for established social groups, but also for minimal groups assigned by novel or random social categorisation. Moreover, whether these ‘ingroup biases’ are related to self-processing is unknown. Across three experiments, we utilised a social associative matching paradigm to examine whether the cognitive mechanisms underpinning the effects of minimal groups overlapped with those that prioritise the self, and whether minimal group allocation causes early processing advantages. We found significant advantages in response time and sensitivity (dprime) for stimuli associated with newly-assigned ingroups. Further, self-biases and ingroup-biases were positively correlated across individuals (Experiments 1 and 3). However, when the task was such that ingroup and self associations competed, only the self-advantage was detected (Experiment 2). These results demonstrate that even random group allocation quickly captures attention and enhances processing. Positive correlations between the self- and ingroup-biases suggest a common cognitive mechanism across individuals. These findings have implications for understanding how social biases filter our perception of the world.