Disentangling the Intergroup Sensitivity Effect: Defending the Ingroup or Enforcing General Norms?

Group members reject threatening outgroup criticism compared to the same criticism from the ingroup (intergroup sensitivity effect [ISE]). Uninvolved bystanders (i.e., members of third groups) also view intergroup criticism as inappropriate. Classic ISE studies were largely underpowered, used inconsequential self-reports, and no study has observed behavioural responses of bystanders versus ingroup members. We argued that norms may elicit self-report responses but only social identity concerns of highly identified ingroup members should motivate costly behaviour. Contrary to our prediction, a high-powered and pre-registered 2 (Source: same-group vs. outgroup) × 2 (Target: ingroup vs. uninvolved outgroup) experiment revealed a classic ISE and an even larger bystander ISE in self-reports and behaviour, favouring a norm account. Moreover, a target effect emerged such that people were more sensitive to criticism targeting an outgroup than their ingroup. Identity thus had an impact, but not in line with social identity theory, highlighting the need for theoretical integration.