Sample selection and inductive generalization

In two experiments with adults (N=126), we examined the influence of sampling procedure on inductive generalization. In predicate sampling, participants learned the category identity of individuals known to possess some property. In subject sampling, individuals selected for category identity were discovered to possess a novel property. In both experiments, sampling procedure influenced induction. Predicate sampling resulted in very narrow generalization, whereas subject sampling yielded a fairly high and constant rate of projection. Differences in confidence of generalizations were also observed. Conditions in which evidence was described as randomly sampled from a collection of animals yielded a consistent decrease in projections as predicted by similarity-based models. The results are presented as support for an evidence-based view of induction.