Explicitly contrasted against a social cohesion based definition for social groups is the social identity perspective, which draws on insights made in social identity theory. Here, rather than defining a social group based on expressions of cohesive social relationships between individuals, the social identity model assumes that "psychological group membership has primarily a perceptual or cognitive basis." It posits that the necessary and sufficient condition for individuals to act as group members is "awareness of a common category membership" and that a social group can be "usefully conceptualized as a number of individuals who have internalized the same social category membership as a component of their self concept." Stated otherwise, while the social cohesion approach expects group members to ask "who am I attracted to?", the social identity perspective expects group members to simply ask "who am I?"