Diversity in a Contrast Set Increases Generalization from a Single-Item Target

Four experiments explored the effect of diversity of contrasting negative evidence on inductive inferences drawn from a single-item target. In Experiments 1 and 2, we found that increasing the diversity of a contrast set led people to infer that a target exemplar corresponded to a higher level category and led to greater generalization of a novel property associated with the target. Further, we demonstrated two boundary conditions in which the effect only occurred when the contrast set was consistent with a higher level category that both united the contrast exemplars and distinguished them from the target (Experiment 4) and when contrast and target shared an obvious parent category (Experiment 5). Taken together, these findings demonstrate that increasing the diversity of a contrast increases generalization from a target, but only if the contrast set is drawn from a single category that excludes, but shares a common parent with, the target.