The out-group homogeneity effect is the perception of out-group members as more similar to one another than are in-group members, e.g. "they are alike; we are diverse". Perceivers tend to have impressions about the diversity or variability of group members around those central tendencies or typical attributes of those group members. Thus, outgroup stereotypicality judgments are overestimated, supporting the view that out-group stereotypes are overgeneralizations.
Social norms are shared standards of acceptable behavior by groups. Social norms can both be informal understandings that govern the behavior of members of a society, as well as be codified into rules and laws. Social normative influences or social norms, are deemed to be powerful drivers of human behavioural changes and well organized and incorporated by major theories which explain human behaviour. Institutions are composed of multiple norms.
Conformity is the act of matching attitudes, beliefs, and behaviors to group norms, politics or being like-minded. Norms are implicit, specific rules, shared by a group of individuals, that guide their interactions with others. People often choose to conform to society rather than to pursue personal desires - because it is often easier to follow the path others have made already, rather than forging a new one. Thus, conformity is sometimes a product of group communication.
In-group favoritism, sometimes known as in-group–out-group bias, in-group bias, intergroup bias, or in-group preference, is a pattern of favoring members of one's in-group over out-group members. This can be expressed in evaluation of others, in allocation of resources, and in many other ways. This effect has been researched by many psychologists and linked to many theories related to group conflict and prejudice. The phenomenon is primarily viewed from a social psychology standpoint.
The social norms approach, or social norms marketing, is an environmental strategy gaining ground in health campaigns. While conducting research in the mid-1980s, two researchers, H.W. Perkins and A.D. Berkowitz, reported that students at a small U.S. college held exaggerated beliefs about the normal frequency and consumption habits of other students with regard to alcohol. These inflated perceptions have been found in many educational institutions, with varying populations and locations.
