This study is designed to investigate the predictions of a connectionist model of the development of inductive inference (Loose & Mareschal, 1997). We demonstrate that adults sometimes use perceptual as opposed to label information when reasoning about a taxonomically structured domain (biological kinds). Thirty six participants were taught the names of a set of tropical seeds. Participants believed that they were learning about real seeds, however the stimuli were constructed after the predictions of the model. Participants were taught that one seed had a particular non-perceptual property, and that a second did not. The task was to infer whether a third seed would have this property. In some cases, the third seed was given the appearance of one seed type, but the name of another. The results supported the model's prediction that participants would make perceptually based inferences in this condition (N = 32, /=2.18, p<0.05). These results stand in contrast to previous work using this experimental paradigm (e.g. Gelman & Markman, 1986). The results challenge previous interpretations of inference behavior to recognize that the use of perceptual information as a guide depends in part on the perceptual structure of the category in question, and is not simply explained by an appeal to conceptual representation in terms of causal "theory" structures.

We present a connectionist model of children's developing reliance on object labels as opposed to superficial appearance when making inductive inferences. The model learns to infer a fact about an object based on the object's label (and not percept) even though that fact has never been previously associated with the label. The shift in reliance from perceptual to label information is found to depend on; (a) the presence of a pre-linguistic ability to categorize perceptual information, and (b) the greater variability of percepts than labels. The model predicts that children will shift their inductive basis at different ages depending on the perceptual variability of the test categories. This prediction is discussed with respect to studies of children's induction and with particular reference to conflicting results reported in the literature concerning the onset of label use.

Previous studies of children's inductive reasoning have attempted to demonstrate that label information is preferred to perceptual similarity as the basis for inductive inference (Gelman and Markman, 1986; Gelman and Markman, 1987; Gelman, 1988). A connectionist model of the development of inductive reasoning predicts that this will only be true when the percepnial variability of category exemplars is high (Loose and Mareschal, 1997). W e report three studies investigating the model's predictions. Study 1 demonstrates that patterns of categorization can depend on percepnial variability. In study 2 we develop a set of stimuli with differing variability but equal discriminability. Study 3 demonstrates that young children's patterns of reasoning are more affected by the presence of category labels when the inference is from an exemplar of a more perceptually variable category. This study also demonstrates that the basis of inference is not explicable in terms of the ease of the ability to categorize of the stimuli. Implications for the original model are discussed.