Both Allport and Social Identity Theory require minimal ingroup identification for bias

Evidence

From these thumbnail sketches, three points are apparent. First, Tajfel and Turner (1986), like Allport before them, place the concept of social identification at the center of their analysis of intergroup relations. Although neither theory posits identification to be the exclusive determinant of biased intergroup attitudes – for example, both accept that real conflicts are also important causes of prejudice – an assumption common to both is that some minimal level of ingroup identification is necessary for such favoritism. A second commonality is that ingroups can vary in their psychological significance for their members, either across individuals or across situations. This is most explicit in Brewer’s model which strongly echoes Allport’s emphasis on variations in group importance with differences in size and inclusiveness. In other words, these theories consider identity to be contextually specific. — John F. Dovidio, Peter Glick, Laurie A. Rudman, On the Nature of Prejudice, 434

First, Tajfel and Turner (1986), like Allport before them, place the concept of social identification at the center of their analysis of intergroup relations. Although neither theory posits identification to be the exclusive determinant of biased intergroup attitudes – for example, both accept that real conflicts are also important causes of prejudice – an assumption common to both is that some minimal level of ingroup identification is necessary for such favoritism. — , Rudman, Laurie A - On the Nature of…, 434

Categorization

• XREF: Connects to my interest in Milgrom’s reputation institutions — minimal group membership as a sort of minimum viable social capital trigger. — connects to: High group identification alone need not produce ingroup bias or discrimination — Nyla R. Branscombe and Bertjan Doosje (eds.), Collective Guilt: International…, 862; the MOC “The Wound of the Label: When Knowing Someone Becomes a Way of Erasing Them”; the MOC “The False Compass: How Racial Categories Reorder Bodies, Minds, and the Self”
• corroborated: 3 independent passages support this claim — John F. Dovidio, Peter Glick, Laurie A. Rudman, On the Nature of Prejudice: Fifty Years…, 434; , Rudman, Laurie A - On the Nature of…, 434