Researchers, however, question these assumptions: based on empiric data from both experiments and ethnographies they suggest that clique structure characterizes many friendship networks within any given school, not all of which negatively affect adolescents.
More subtle determinant of group membership, such as shared interests and values, take precedence as adolescents develop more sophisticated, abstract cognitive functions (more here), which allow them to categorize individuals in more subtle ways and better interpret social interactions.
In general, cliques first form in early adolescence with strict gender segregation, but by middle adolescence, some mixed-gender activities within the peer crowds foster close, cross-sex friendships which begin to restructure the clique.
Cliques are different from other types of peer groups often seen in the average school, which are often reputation-based groups such as jocks or nerds.
Some of the more common types of cliques found include: jocks, tomboys, cheerleaders, mean girls, foreigners, gamers, hipsters, hippies, troublemakers, peacemakers, class clowns, "cool kids", arty intellectuals, gangsters, wangsters, "ghetto kids", stoners/slackers, girly girls, scenesters, scene kids, punks, preps, skaters, goths, emos, skinheads, geeks/nerds, and drifters.