The social identity theory was first developed by Tajfel and his colleagues in 1979, in the context of trying to explain prejudice and discrimination. Prejudice and discriminations are basically a result of stereotypes.Prejudice is an attitude while discrimination is a behavior.According to the Realistic conflict theory by Sherif et al.(1961),prejudice arises as a result of a conflict of interests. Tajfel however disagreed with Sherif and argued that the mere fact of categorization is enough to cause ingroup bias.
An example of minimal group experiment ,(an experiment where people are assigned to groups on the basis of very minimal identifications), that explains thoroughly the social identity theory is the following .Tajfel “et al” recorded a study where 14 and 15 year old school boys from Bristol were assigned to one of two groups. They didn’t know the other members of their team . The experimenter led them to believe that they were assigned to groups based on their preference between Klee or Kandinsky .Each of the boys worked on his own trying to make a decision about how to allocate points to a member of their own group and a member of the other group.The results were completely rational and justifiable .The boys showed an ingroup favoritism ,preferring to allocate more points to their ingroup instead of the outgroup. In addition,they showed a positive distinctiveness since they preferred the option where they would allocate points to their team having the maximum difference with the outgroup ,sacrificing some points for their team.
In order to fully justify the choices the participants did from the above experiment, we base our assumptions on the social identity theory ;a part of our self-concept that is based on knowledge of our membership of one or more social groups. It is seraprate from the personal identity,which is the part of the self-concept that derives from the way we perceive our personality traits