Social identity theory (SIT) attempts to understand how social categorization affects intergroup behaviours (Tajfel and Turner, 1979).
SIT is associated with a number of pioneering studies, most of which rely on the ‘minimal group paradigm’. In recent years, SIT has been explored with the use of additional types of study but I am going to discuss studies using the minimal group paradigm. Such studies are directly relevant to the evaluation of the theory and several have been instrumental in its development.
SIT is based on a number of inter-related concepts: social categorization, social identity, social comparison and positive distinctiveness. Social categorization divides the social environment into ingroups (to which an individual belongs) and outgroups (to which the individual does not belong). Social identity is the part of our self-concept based on knowledge of our membership of one or more social groups. It is separate from personal identity – which is the part of our self-concept that derives from the way we perceive our personality traits and the personal relationships we have with other people (Turner, 1982). Whereas personal identity is associated with interpersonal behaviours, social identity is related to intergroup behaviours.
Our social identity contributes to how we feel about ourselves, so we seek positive social identities to maintain and enhance our self-esteem. Positive social identities may result from the process of social comparison as we continuously compare our ingroups with relevant outgroups. This social comparison process is set in motion by our need for positive distinctiveness – the motivation to show the superiority of our ingroup compared to relevant outgroups. By thus establishing the superiority of our ingroup, we make sure that our social identities, and therefore our self-esteem, are positive enough.
Intergroup behaviours, the study of which forms the focus of SIT, are based on social identities and exhibit the following general characteristics:
• ingroup favouritism (the tendency to behave in ways that favour members of our ingroup compared to members of outgroups)
• intergroup differentiation (behaviour that emphasizes differences between our ingroup and outgroups)
• ethnocentrism (an ingroup-serving bias: positive behaviours by ingroup members tend to be internally attributed whereas negative behaviours receive a situational attribution; the reverse pattern is manifested when explaining positive and negative behaviours in an outgroup)
• conformity to ingroup norms (much greater than conformity to outgroup norms)
• stereotypical thinking (ingroupers and outgroupers are all perceived according to relevant stereotypes).
In this essay, I will concentrate on the crucial SIT phenomena of ingroup favouritism and intergroup differentiation. The other characteristics listed above highlight the diversity of phenomena that have been constructively addressed by SIT.
SIT has been supported by many experiments using the minimal group paradigm introduced by Tajfel (e.g. Tajfel et al., 1971). The technique defines ingroups and outgroups on arbitrary criteria such as by tossing a coin. Group members never meet or in any other way interact with one another. In fact, they do not even know who else belongs to their ingroup or to the outgroup. Tajfel et al. (1971) is an early study of this type.
Tajfel et al. (1971) divided a number of British schoolboys into two groups. Although the experimenters allocated the participants randomly to the two groups, the participants were led to believe that the groups were defined on the basis of a preference for paintings by either Klee or Kandinsky. The boys, who worked individually, had to distribute points to ingroup and outgroup members. They were not allowed to give points to themselves. Tajfel et al. were interested to see how the participants distributed the points.
The boys showed a strong tendency to favour members of their ingroup over members of the outgroup, thus manifesting ingroup favouritism. Their strategies also provided evidence for the SIT notion of positive distinctiveness. On many occasions, the boys would sacrifice point gain for their ingroup in order to maximize the difference in point gain between their ingroup and outgroup. For example, when given the choice, participants gave an ingroup member 7 points and an outgroup member 1 point, rather than giving both 13 points as they could have done.
There are hundreds of studies using the minimal group paradigm, most supporting the major tenets of SIT (Hogg and Vaughan, 2008). However, minimal group paradigm research has been criticized: perhaps the effects obtained are the result of participants responding to demand characteristics. As the minimal group effect can be obtained even when the participants do not know they are being observed, this does not seem to be likely (Grieve and Hogg, 1999). Moreover, ingroup favouritism and outgroup discrimination have been repeatedly demonstrated in natural settings with real-life groups. Brown (1978), for example, carried out a field study of wage negotiations in a British aircraft engineering factory. He found that trade union representatives from one department sacrificed about £2 a week in order to increase their relative advantage over a competing outgroup to £1.
The strength of the minimal group effect varies depending on a number of factors. Mummendey and Otten (1998) found that it is more powerful when participants distribute positive resources (e.g. points) and weaker, if present at all, with negative resources (e.g. punishment). The strength of the minimal group effect can also be reduced when participants have to justify their allocation of resources to ingroup and outgroup members (Dobbs and Crano, 2001).
The self-esteem hypothesis, which figured extensively in the original statement, is no longer viewed as central to SIT. Some studies have shown that the increase in self-esteem associated with outgroup discrimination is too short-lived to have long-lasting effects on how ingroup members view themselves (Rubin and Hewstone, 1998).
In conclusion, SIT has demonstrated the crucial role of social categorization in intergroup behaviour and the importance of distinguishing between personal identity and social identity. Moreover, it has contributed very significantly to the explanation of an impressive list of social psychological phenomena, including conformity and stereotyping. The original SIT theory has expanded over the years and continues to generate a lot of research. Starting with Tajfel’s pioneering minimal group studies, SIT has been supported by hundreds of relevant empirical studies.
Despite its shortcomings (e.g. problems with the self-esteem hypothesis), SIT has stood the test of time and continues to make substantial contributions to our understanding of intergroup behaviour (Hogg and Vaughan, 2008).