Assimilation and contrast as a function of people's willingness and ability to expend effort in forming an impression.

Set/reset (Martin, 1986) hypothesis that contrast demands more cognitive effort than does assimila-tion was examined. In Exp. 1, the impressions of distracted Ss showed assimilation toward blatantly primed concepts, whereas the impressions of nondistracted Ss showed contrast. In Exp. 2, Ss told that their ratings would be lumped into a group average showed assimilation, whereas Ss told that their ratings would be examined individually showed contrast. In Exp. 3, the impressions of Ss low in need for cognition showed assimilation, whereas the impressions of Ss high in need for cognition showed contrast. Exp. 1 also showed that the results were not due to differences in recall of the target information, and Exp. 3 showed that the results were not due to differences in recall of the priming stimuli. Together, the results suggest that the processes involved in contrast demand more cognitive effort than do the processes involved in assimilation. The context in which a stimulus is embedded can have signifi-cant effects on peoples judgment of that stimulus. The two effects that have been most reliably demonstrated are assimila-tion and contrast. Assimilation refers to a positive relation be-tween the value people place on a target stimulus and the value they place on the contextual stimuli that accompany the target. Contrast refers to a negative relation between these two values (cf. Sherman, Ahlm, Berman, Lynn, 1978). The terms assimi-lation and contrast are generic in the sense that they refer simply to the direction of context effects, and not to the processes underlying them. It is not unreasonable to assume, therefore, that there are different kinds of assimilation and contrast that involve different kinds of processes (cf. Wedell, in press). The factor most frequently considered in the explanation of assimilation and contrast is the distribution of the contextual