People often reflect on the opinions of others and express greater attitude certainty when they perceive their attitudes to be shared by others (high attitude consensus). The present research tests the possibility that either high or low attitude consensus can increase attitude certainty depending on people's salient social identification needs. In particular, high attitude consensus with a target group is found to be more validating when people seek to belong to the group, as this identification motive promotes a search for similarities between themselves and the group. In contrast, low attitude consensus with a target group is found to be more validating when people seek to be unique from a group, as this identification motive promotes a search for dissimilarities between themselves and the group. Two experiments support these hypotheses, offering insight into the intra-personal motives that alter the diagnostic value of social consensus information.