The present study investigated the social and relational bases of the availability bias. The availability heuristic refers to the tendency to judge events to be more likely or frequent when instances thereof come more easily to mind (Tversky & Kahneman, 1973). Tversky and Kahneman (1973) cite the example of a tendency to overestimate the risk of road accidents after witnessing an accident because of the availability of such vivid information during judgment. We argue that the availability of information can be a function of the relevance of such information to the perceiver. Following self-categorization theory (Turner, Hogg, Oakes, Reicher & Wetherell, 1987) we predicted that the self-relevance of target information would be enhanced where target and perceiver share a common group membership or social identity, providing a basis for assumed similarity. This led to the hypothesis that availability and judgments of risk would be greater when prior information about a road accident implicated an ingroup rather than an outgroup, or than when no information was provided. This hypothesis was tested in an experiment which orthogonally manipulated both the social identity of physics student subjects (“physicist” vs. “scientist” identities were rendered salient) and stimulus information about the victims of a road accident (physicists, psychologists, construction workers, no information), such that the victims could either be defined as belonging to or excluded from the ingroup. The hypothesis was strongly supported on a number of indices of perceived risk. No significant differences obtained between outgroup and no information conditions. These findings suggest that the effect of availability on judgments of risk was mediated by the perceived relation of target stimuli to it. (Author/publisher)
Abstract