Distinguishing among models of contextually induced preference reversals.

Previous research has demonstrated that adding a 3rd (decoy) alternative that is dominated by only 1 of the other 2 alternatives in a choice set increases the preference for the dominating alternative (J. Huber, Payne, Puto, 1982; Tyszka, 1983). By manipulating decoys within subjects, significant preference reversals have been obtained. The processes of 3 classes of models can account for these reversals: (a) The decoy affects the weights assigned to different dimensions, (b) the decoy produces range-frequency effects on the dimensional values of the alternatives, and (c) the perception of dominance directly increases the attractiveness of the targeted alternative. The results of 3 experiments designed to test these models favored a direct effect of dominance. When a dominated decoy was added to a choice set, asymmetrical dominance was demonstrated to be a necessary and sufficient condition for producing the predicted preference reversals. Preference reversals have intrigued decision scientists in much the same way that visual illusions have captured the attention of researchers investigating visual perception. In each case, the respective cognitive system appears to operate reasonably well in the normal environment. Yet, when