Self-Categorization Theory

Self-categorization theory is a social-cognitive elaboration of social identity theory that provides an account of identity salience, or what identities people are most likely to internalize when and why. The core idea is that people have a repertoire of available identities and that these are activated by and take on meaning with respect to social context. When an identity is activated, the associated content predicts social perceptions, attitudes, emotions, and behaviors. Although consistent with the metatheoretical logic of social identity theory (that social psychological outcomes are a function of individual psychology interacting with social context), self-categorization theory expands the scope to explain such phenomena as stereotyping, social influence, group cohesion, and intragroup process.

Self-categorization theory begins with the assumption that people maximize meaning—that they organize a perceptual field so that it makes sense. This is not to say that people are in any way motivated to create meaning. Rather, the idea is that they extract meaning from stimuli by automatically organizing them into categories. A rainbow, for example, is a continuous spectrum of color, but we cognitively represent a rainbow as comprising a set of discrete bands. Each band is perceived as homogenous and distinct from the adjacent band.

More generally, categorization follows the metacontrast principle. Stimuli are perceived as comprising a category to the extent that shared similarities exceed differences with other stimuli. [Page 871]A researcher would give participants a scale and measure their individual perceptions of the differences between possible categories and calculate the average. The researcher would also measure participants' individual perceptions of the differences within a possible category and calculate the average. The metacontrast ratio is the average intercat-egory difference divided by the mean intracategory difference, and the ratio between these provides a measure of the extent to which a set of stimuli will be perceived as a category. The more the ratio exceeds unity, or 1, the greater the probability that a category will be perceived. Although this explains the perceptions of nonsocial objects such as trees and rocks as categories, additional considerations are necessary to predict when social categories such as people and relationships become salient.

Before elaborating on the other features of social categorization, it is first worth noting that social categories are cognitively represented as context-dependent prototypes. Prototypes are fuzzy sets of features that best represent a category, and they do so by following the metacontrast principle. For example, compared with Iraqis, Americans might be considered White, individualistic, and Christian, a set of attributes that Americans tend to share and that are not shared with most Iraqis. Compared to the British, however, Americans might be better described as brash, outgoing, and overweight. Because the content of prototypes shifts to make best sense of an identity in a particular context, it is also true that individual people can be more or less prototypical in different contexts. George W. Bush might be considered a quite prototypical American when the comparison is with Iraqis, but John Belushi might be a better example for the comparison with the British. Critically, people internalize the features of prototypes; they self-stereotype or are depersonalized by the prototype, and this provides the content to identity that predicts social outcomes.

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