The present study examined the effects of semantic structure on simple inductive judgments about category members. For a particular category, subjects were told that one of the species had a given property and were asked to estimate the proportion of instances in the other species that possessed the property. The results indicated that category structure—in particular, the typicality of the species—influenced subjects' judgments. These results were interpreted by models based on the following assumption: When little is known about the underlying (...) distribution of a property, subjects assume that the distribution mirrors that of better-known properties. For this reason, if subjects learn that an unknown property is possessed by a typical species, they are more likely to generalize than if the same fact had been learned about an atypical species. (shrink)

Linguistic form and conceptual level both play a role in the structure of adult lexical hierarchies. The present studies examined how these factors might affect acquisition. In their linguistic form, labels can be single nouns or compound nouns. In conceptual level, categories can be structured at the basic, superordinate, or subordinate levels. Both of these factors were varied in two experiments, in which 133 children, aged 2;11 to 5;11, were taught novel lexical hierarchies. As predicted, compound nouns were easier to (...) learn than single nouns, especially at the subordinate level. Age of child and category level influenced the kinds of errors children made. The most common error was to treat hierarchically related words as labeling mutually exclusive subsets, so that terms from different levels contrasted at the same level. Both factors--linguistic form and conceptual level--influenced children's learning of new lexical hierarchies. (shrink)