When hearsay trumps evidence: How generic language guides preschoolers' inferences about unfamiliar things

Two experiments investigated 4-year-olds' use of descriptive sentences to learn non-obvious properties of unfamiliar kinds. Novel creatures were described using generic or nongeneric sentences (e.g., These are pagons. (Pagons) under bar/(/These) under bar (pagons) under bar are friendly). Children's willingness to extend the described property to a new category member was then measured. The results of Experiment 1 demonstrated that children reliably extended the property to new instances after hearing generic but not nongeneric sentences. Further, the influence of generic language was much greater than effects related to the amount of tangible evidence provided (the number of creatures bearing the critical property). Experiment 2 revealed that children continued to extend properties mentioned in generic descriptions even when incompatible evidence was presented (e.g., an example of an unfriendly 'pagon'). The findings underscore preschoolers' keen understanding of the semantics of generic sentences and suggest that inferences based on generics are more robust than those based on observationally grounded evidence.