Two experiments are reported which demonstrated intransitivity in category judgments, thus challenging a widely held assumption that the relation between categorized sets is one of class inclusion. Subjects consistently accepted the truth of certain category statements, in spite of being aware of the existence of counterexamples. Implications for semantic memory theory are discussed.

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)

Children's reasoning about biological concepts is influenced not only by their experiences in the natural world and in their classrooms, but also by the way that these concepts are named. In English, 'animal' can refer either to exclusively non-human animals, or all animate beings. In Indonesian, this category of animate beings has no dedicated name. Here, we ask whether this difference in naming has consequences for children's reasoning about humans and non-human animals. Results from English- and Indonesian-speaking children reveals differences (...) in reasoning at age 6, differences that become attenuated by age 9. These results suggest that not only naming practices, but also biologically-relevant formal and informal learning experiences, influence children's reasoning about biological concepts. (shrink)