Tajfel (1979) proposed that the groups (e.g. social class, family, football team etc.) which people belonged to were an important source of pride and self-esteem.
We divide the world into “them” and “us” based through a process of social categorisation.
This is known as in-group (us) and out-group (them). Social identity theory states that the in-group will discriminate against the out-group to enhance their self-image.
Prejudiced views between cultures may result in racism; in its extreme forms, racism may result in genocide, such as occurred in Germany with the Jews, and in Rwanda between the Hutus and Tutsis
In social identity theory the group membership is not something foreign or artificial which is attached onto the person, it is a real, true and vital part of the person.