Social Identity Theory as an explanation of prejudice
Tajfel and Turner (1979) suggested that prejudice comes from the formation of two
groups and does not need any other factor to cause conflict.
The social identity theory argues that an individual’s self concept is related to the
groups they are members of. Any person is a member of many groups and their
social identity comes from how they see themselves in relation to those groups.
Belonging to a group is essential to a person’s self esteem according to this theory.
This is increased even more by being part of a successful and high status group.
There are three cognitive processes involved in becoming prejudiced against
members of other groups:

Social Categorisation: seeing oneself as part of a group.
The group we belong to is our in-group. Other groups are
automatically out-groups. This process of categorisation
happens very quickly in any situation where we are either
assigned to a group or choose to join the group ourselves.

Social Identification: once we have categorised ourselves
as belonging to a group, we then adopt the identity of the
group. We follow the behavioural norms of the group. This
identification is emotionally significant and may be the basis
for a lot of our self-esteem.

Social Comparison: to maintain our self-esteem it is
important that we believe our group is better than other
groups. Hostility that can occur between groups can then lead
to discriminatory behaviour towards members of the outgroup.
There are three variables that can affect in-group favouritism:
1. How strongly the group members identify with the group
2. Whether there are grounds for comparison with the other group
3. How relevant the other group is to the in-group members
Clearly there are different causes of prejudice such as race, culture or age
differences. Tajfel recognised also that competition between groups would increase
prejudice and discrimination. He did believe, however that prejudice and
discrimination could happen without competition and all that was necessary was the
formation of two groups.