The authors draw upon the principles of the social identity tradition in order to elaborate a psychological model of mass communication. This centres on the way in which people construe their social identities and the meanings of events for these identities. They then go on to look at the ways in which these principles have been employed both to mobilize collective support for genocide and collective resistance to genocide. They conclude that it is critical to understand these principles and to apply them effectively in order to promote social harmony and the defence of vulnerable groups.