Context effects in decision making : Attraction, phantom, and plurality effects

Abstract

Preferences between two alternatives are influenced by the presence of a third alternative, regardless of whether it is superior or inferior to the first two. Range frequency theory explains that these effects are due to the categorical changes of the attributes of the alternatives. The dominance valuing hypothesis states that dominant alternatives have extra value through the greater justifiability of the choice. The trade-off contrast and extremeness aversion hypotheses assume that the relative merits among alternatives change when the third alternative is compared to the others. The present study proposed that the above effects were due to a shift of the neutral point and the negativity effect in ambivalent evaluation. One hundred forty eight undergraduates in Study 1 and 137 undergraduates in Study 2 participated in hypothetical decision problems. The results suggested that equivalent (plurality), as well as inferior (attraction) and superior (phantom), decoys enhanced the preferences of the targets when the decoys were unavailable. These results support the ambivalence model of evaluation.