The role of expectations in comparisons

Expectations are proposed as a unifying framework for explaining a variety of findings on comparative judgment. Expectations may pertain to either the features of each separate object or their simultaneous occurrence in all r elevant objects. Two experiments demonstrate that inducing expectations by varying the frequency with which a component occurs, as well as the frequen cy with which it is shared by the compared objects, results in augmented we ighting of unexpected components. Expectations can arise not only from expe rienced frequencies but also from an inferred set of alternatives. Features of cohesive stimuli are shown to be more expected than features of noncohe sive stimuli, in the latter sense. The relatively higher weighting of disti nctive features in cohesive stimuli, as well as the higher weight assigned to structurally aligned differences, could thus reflect modifications in fe ature expectedness. Further experiments show how task-dependent weighting i nteracts with expectations to produce asymmetries between similarity and di fference judgments. Finally, it is argued that changes in expectations rega rding objects' attributes can explain context effects across different doma ins, including some types of preference reversals.