Translating testimonial claims into evidence for category-based induction
Inductive generalizations about the properties of kinds are based on evidence. But evidence can come either from our observations, or from the testimony of knowledgeable informants. The current study explores how we combine information from these two sources to make inductive inferences. Participants learned about a novel object category, and observed the property occur with some frequency in a sample of category members. Different groups of participants also heard an informant making either Generic, Quantified, or Specific claims about the prevalence of the property. Participants who heard generic claims were more resistant to a straightforward use of statistical evidence in their generalizations. Moreover, participants who rated the informant as more knowledgeable (across conditions) gave higher prevalence estimates. The results suggest two pathways through which testimony translates into evidence for category learning, and raise questions on how to best combine evidence from these different sources into a common representational form.
