Henri Tajfel's greatest contribution to psychology was social identity theory.
Social identity is a person’s sense of who they are based on their group membership(s).
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. Groups give us a sense of social identity: a sense of belonging to the social world.
In order to increase our self-image we enhance the status of the group to which we belong. For example, England is the best country in the world! We can also increase our self-image by discriminating and holding prejudice views against the out group (the group we don’t belong to). For example, the Americans, French etc. are a bunch of losers!
Therefore, we divided the world into “them” and “us” based through a process of social categorization (i.e. we put people into social groups).
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.
The central hypothesis of social identity theory is that group members of an in-group will seek to find negative aspects of an out-group, thus enhancing 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, in Rwanda between the Hutus and Tutsis and, more recently, in the former Yugoslavia between the Bosnians and Serbs.
Henri Tajfel proposed that stereotyping (i.e. putting people into groups and categories) is based on a normal cognitive process: the tendency to group things together. In doing so we tend to exaggerate:
1. the differences between groups
2. the similarities of things in the same group.
We categorize people in the same way. We see the group to which we belong (the in-group) as being different from the others (the out-group), and members of the same group as being more similar than they are. Social categorization is one explanation for prejudice attitudes (i.e. “them” and “us” mentality) which leads to in-groups and out-groups.
o Northern Ireland: Catholics Protestants
o Rwanda: Hutus and Tutsis
o Yugoslavia: the Bosnians and Serbs
o Germany: Jews and the Nazis
o Politics: Labor and the Conservatives
o Football: Liverpool and Man Utd
o Gender: Males and Females
o Social Class: Middle and Working Classes
Tajfel and Turner (1979) proposed that there are three mental processes involved in evaluating others as “us” or “them” (i.e. “in-group” and “out-group”. These take place in a particular order.
The first is categorization. We categorize objects in order to understand them and identify them. In a very similar way we categorize people (including ourselves) in order to understand the social environment. We use social categories like black, white, Australian, Christian, Muslim, student, and bus driver because they are useful.
If we can assign people to a category then that tells us things about those people, and as we saw with the bus driver example, we couldn't function in a normal manner without using these categories; i.e. in the context of the bus.
Similarly, we find out things about ourselves by knowing what categories we belong to. We define appropriate behavior by reference to the norms of groups we belong to, but you can only do this if you can tell who belongs to your group. An individual can belong to many different groups.
In the second stage, social identification, we adopt the identity of the group we have categorized ourselves as belonging to. If for example you have categorized yourself as a student, the chances are you will adopt the identity of a student and begin to act in the ways you believe students act (and conform to the norms of the group). There will be an emotional significance to your identification with a group, and your self-esteem will become bound up with group membership.
The final stage is social comparison. Once we have categorized ourselves as part of a group and have identified with that group we then tend to compare that group with other groups. If our self-esteem is to be maintained our group needs to compare favorably with other groups.
This is critical to understanding prejudice, because once two groups identify themselves as rivals, they are forced to compete in order for the members to maintain their self-esteem. Competition and hostility between groups is thus not only a matter of competing for resources (like in Sherif’s Robbers Cave) like jobs but also the result of competing identities.
Just to reiterate, 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.
Again, it is crucial to remember in-groups are groups you identify with, and out-groups are ones that we don't identify with, and may discriminate against.
Tajfel, H., & Turner, J. C. (1979). An integrative theory of intergroup conflict. The social psychology of intergroup relations?, 33, 47.
McLeod, S. A. (2008). Social Identity Theory. Retrieved from www.simplypsychology.org/social-identity-theory.html