| Abstract: | This paper investigates models that describe how subjects combine uncertain information to arrive at an intuitive prediction of a criterion. Subjects were trained, with feedback, to predict a numerical criterion from each of three single cues. Then they were asked to predict the criterion, without feedback, either from pairs of cues or from single cues. Their predictions were not consistent with a relative weight averaging model, since pairs of cues did not combine additively. Instead, the effect of a cue was inversely proportional to the standard deviation of the criterion at each level of the cue. Subjects appeared to apply greater weight to cue levels with smaller variance, i.e., those cue levels that were more valid. The data could be described by a distributional theory referred to as the equal probability model. For the present experiment, this model implies that the criterion means associated with the levels of each cue are weighted by the reciprocals of the standard deviations and then averaged. Relations between the equal probability model and other models of impression formation are discussed. |
