In three experiments, students completed sets of three pairwise choices in each of several domains. The first two pairs in each set were contextual pairs, and the third was the target pair. Context was manipulated by widening the range of values on one dimension and narrowing it on the second dimension. Consistent with previous research, participants on target trials more often chose the alternative whose poorer value was on the widened dimension. Four models explained this effect as (a) decreased weighting of the wide dimension, (b) contextual shift in values, (c) a tendency to equalize responses, or (d) a tendency to add value based on dominance relationships. Path models provided evidence against weight change and response equalization, and manipulation of dominance did not reduce the effect. Results supported the value-shift explanation of trade-off contrast.When choosing between multiattribute alternatives, one is faced with the problem of having to make trade-offs between values on different attributes. For example, imagine a choice between two cars that differ primarily on the dimensions of gas mileage and safety features. Would you choose the car that gets high gas mileage but has few safety features or the one that gets low gas mileage but has many safety features? Ultimately the choice depends on whether the increase in gas mileage is worth the decrease in safety: a trade-off.How are such trade-offs resolved? One approach to the problem is given by multiattribute utility theory, in which preference values are assigned to each level on a dimension and importance weights are assigned to the different dimensions (Von Winterfeldt & Edwards, 1986). The overall utility of an alternative is determined by combining weights and values, typically using a weighted additive model:( 1) where Vy is the preference value of alternative i on attribute/ Wj is the weight assigned to that attribute, and m indexes the set of relevant attributes. The choice rule is then to select the alternative with the highest overall attractiveness or utility, a difference operation. If one considers a dimensionwise processor of information in a pairwise choice situation, the weighted additive model can give rise to the weighted difference model. When Equation 1 is rearranged, the difference in utilities for two alternatives can be expressed as