Belief Instability as a Mediating Variable in Opinion Change: The Effects of Attack Discrepancy

According to the uncertainty model of opinion change, a persuasive message induces instability in the recipient's belief system. Opinion change is then a function of the degree of instability which has been induced. Subjects possess a repertoire of arguments to bolster beliefs which support their own attitudes, and another repertoire to refute messages advocating opposite beliefs; they are less well-prepared to counter messages which are only moderately discrepant, and such messages should consequently induce the most instability. Thus there is a curvilinear relationship between attack discrepancy and belief instability or uncertainty, as measured by inconsistencies in the ranking of belief-relevant statements. The relationship between instability and opinion change is positive and linear. Data from an experiment using messages of various degrees of extremeness opposing the use of automobile seat-belts supported these hypotheses. Furthermore, subjects whose own attitudes had been previously made salient showed more uncertainty after a mildly discrepant and less after a severely discrepant message. The uncertainty model, which is based upon an objectively measured intervening variable, provides an unusually exact and testable starting point for hypothesis generation in the field of attitude change.