This paper builds upon Reicher's (1984a) model of deindividuation by arguing that manipulations of identifiability do not only affect the salience of social identity but also have strategic consequences for the expression of in-group stereotypes. Increasing the visibility of group members to a powerful out-group should decrease the ability of those members to express any aspects of their identity which would meet resistance from the out-group. A preliminary study found that making supporters of the Campaign for Nuclear Disarmament individually identifiable to a powerful out-group only affects the incidence of stereotypic behaviours which would be punishable by that out-group. In the main study, science students taking a psychology course are either defined as ‘scientists’ or as ‘students’. They are then asked to complete a questionnaire about the psychology course consisting of items where difference from a staff norm would either be unpunishable or punishable. On the punishable items, the ‘science’ stereotype is compatible with the staff position, while the ‘student’ stereotype is incompatible. As expected, increased visibility of subjects to academic staff decreases conformity to the in-group stereotype for those defined as students but does not affect the behaviour of those defined as scientists. What is more, this pattern of results only holds for the punishable items. However, contrary to expectations, on the unpunishable items, increased visibility increases conformity to the in-group stereotype for both groups. Taken together, the two experiments confirm that immersing individuals in a group where they are anonymous to outsiders not only predisposes them to act in terms of social identity but also blunts out-group power in such a way as to allow full expression of that identity.