Merely categorizing people into us and them generates in-group favoritism and out-group devaluation

Evidence

In the basic paradigm the subjects (both children and adults have acted as subjects in the various studies) are randomly classified as members of two nonoverlapping groups— ostensibly on the basis of some trivial performance criterion. They then make “decisions,” awarding amounts of money to pairs of other subjects (excluding self) in specially designed booklets. The recipients are anonymous, except for their individual code numbers and their group membership (for example, member number 51 of the X group and member number 33 of the Y group). The subjects, who know their own group membership, award the amounts individually and anonymously. The re-sponse format of the booklets does not force the subjects to act in terms of group membership. — John T. Jost and Jim Sidanius, Political Psychology, 2704 (#corroborates, via linked claim)

Working from Tajfel’s (1978) definition, Ellemers, Kortekaas, and Ouwerkerk (1999) identified three separate components of social identity: (1) a derivation of self-concept, in part, from the groups to which one belongs (social categorization), (2) an emotional attachment to one’s group (affective commitment), and (3) an evaluative component in which one favors one’s own group over others (group self-esteem). … Yet, these three components were identified as separate dimensions in a principal components analysis (PCA). They were also differentially affected by group characteristics such as size and status. Ultimately, only group commitment mediated the effects of group characteristics on in-group favoritism. — Roderick M. Kramer, Geoffrey J. Leonardelli, Robert W. Livingston, Social Cognition, Social Identity, and…, 1748 (#contradicts, via linked claim)

When people or objects are categorized into groups, actual differences between members of the same category tend to be perceptually minimized (Tajfel, 1969) and often ignored in making decisions or forming impressions. Members of the same category seem to be more similar than they actually are, and more similar than they were before they were categorized together (see Judd & Park, ch. — John F. Dovidio, Peter Glick, Laurie A. Rudman, On the Nature of Prejudice, 550 (#expands, via linked claim)

Categorization

• XREF: connects to: Collectivist frames attribute causality to whole groups rather than individual actors — Leonard S. Newman and Ralph Erber (eds.), Understanding Genocide: The Social…, 1028; Mere arbitrary group membership, with no interaction, triggers in-group favoritism — John T. Jost and Jim Sidanius, Political Psychology, 2704; Categorizing people into groups minimizes perceived within-group differences — John F. Dovidio, Peter Glick, Laurie A. Rudman, On the Nature of Prejudice: Fifty Years…, 550 (+8 more)

Broader Connections

• Mere arbitrary group membership, with no interaction, triggers in-group favoritism #corroborates (0.90) — John T. Jost and Jim Sidanius, Political Psychology, 2704
• Categorizing people into groups minimizes perceived within-group differences #expands (0.85) — John F. Dovidio, Peter Glick, Laurie A. Rudman, On the Nature of Prejudice, 550
• Only emotional attachment to one’s group, not categorization or self-esteem, drives in-group favoritism #contradicts (0.85) — Roderick M. Kramer, Geoffrey J. Leonardelli, Robert W. Livingston, Social Cognition, Social Identity, and…, 1748
• Ingroup favoritism usually lacks explicit hostility toward outgroups #qualifies (0.85)
• Negational identities produce both out-group derogation and in-group favoritism #expands (0.80) — Roderick M. Kramer, Geoffrey J. Leonardelli, Robert W. Livingston, Social Cognition, Social Identity, and…, 1112
• Feeling closer to ingroup members increases dehumanization of outgroups #expands (0.80) — Norenzayan, Ara, Big gods - how religion transformed…, 529
• Ingroup favoritism operates independently of outgroup hatred #qualifies (0.75) — John F. Dovidio, Peter Glick, Laurie A. Rudman, On the Nature of Prejudice, 1496
• Recategorizing group boundaries can expand ingroup identity from us-them to we #responds-to (0.75) — , Rudman, Laurie A - On the Nature of…, 564