In-group bias intensifies against similar rather than dissimilar out-groups

Evidence

The results showed that the Arts (High Importance) groups were more biased than the Science (Low Importance) groups, that similar groups differentiated more than dissimilar groups in the Stable condition, but that they were no more biased (and sometimes even less so) in the Unstable condition; and that, on some of the measures, there was a significant main effect for out-group similarity: in-group bias increased against a similar out-group. — John T. Jost and Jim Sidanius, Political Psychology, 2729

Categorization

• XREF: Parallels the ‘narcissism of minor differences’ idea found in Freud and later in studies of sectarian conflict among near-identical groups. — connects to: Groups only compare themselves with relevant out-groups, not all available ones. — John T. Jost and Jim Sidanius, Political Psychology: Key Readings, 2721
• QUESTION: Why does similarity heighten bias only when status differences are perceived as unstable? Worth chasing the original Turner 1978b study.