It is through social interactions that have put people to act and react implication to others. Due to the social interactions we learn what is acceptable and what is not. Over time these rules become internalised within us and eventually become an unconscious part of our lives and our identity. Social identity theory asserts that group membership creates in group self-categorisation and enhancement in ways that favour the in group at the expense of the out-group and associating with a group even under minimal circumstances is enough to create in group out-group hostility. I will explore the effects of the contact theory or intergroup behaviour. It is also the aim of this essay to explain what is meant by the term social construction and social categorisation and how these two theories have further to our understanding of identity.