Psychological correlates of certainty strength: Measuring the relative influence of evidence, opinion of personal contacts, and importance to self-identity



This research examines the psychological foundations of personal belief by measuring how different determinants of belief formulation contribute to certainty strength. Together, two studies collected data from over 400 undergraduate students regarding how physical, social and religious beliefs are formulated. Participants rated their strength of belief in these domains relative to the following determinants: the importance of substantiating evidence, the perceived logic inherent in a belief, the importance to self identity, the influence of personal contacts, the social community and authority figures and the expected permanence, perceived relevance and personal likeability of the belief. The present research found that strength of certainty can be predicted by the quality of empirical evidence that people can offer to support the belief, by their estimates of their parent’s certainty in the belief and by the perceived importance of the belief to their sense of self-identity.