 According to Turner, social identity is basically a cognitive mechanism whose adaptive function is to make “group behavior” possible. Whenever social identification becomes salient, a cognitive mechanism of categorization is activated in such a way to produce perceptual and behavioral changes. Such categorization is called a stereotype, the prototypical description of what members of a given category are (or are believed to be). It is a cluster of physical, mental and psychological characteristics attributed to a “typical” member of a given group. Stereotyping, like any other categorization process, activates scripts or schemata, and what we call group behavior is nothing but scripted behavior. For example, the category “Asian student” is associated with a cluster of behaviors, personality traits, and values: we often think of Asian students as respectful, diligent, disciplined, and especially good with technical subjects. When thinking of an Asian student solely in terms of group membership, we attribute her the stereotypical characteristics associated with her group, so she becomes interchangeable with other group-members. When we perceive people in terms of stereotypes, we depersonalize them and see them as “typical” members of their group. The same process is at work when we perceive ourselves as group-members: self-stereotyping is a cognitive shift from “perceiving oneself as unique” to “perceiving oneself in terms of the attributes that characterize the group”. It is this cognitive shift that mediates group behavior.