Young children's use of functional information to categorize artifacts: three factors that matter

Three experiments addressed factors that might influence whether or not young children take into account function, as opposed to overall appearance or shape, when they extend the names of novel artifacts. Experiment 1 showed that 4-year-olds more often extend a name on the basis of a demonstrated function when that function provides a plausible causal account of perceptible object structure. Experiment 2 showed that they more often extend a name by function when they respond slowly, and hence thoughtfully. Experiment 3 demonstrated that they are more likely to take function into account when they extend names than when they judge similarities. Comparisons of lexical and non-lexical conditions in younger children failed to show any differences. Overall, the findings suggest that by 4 years of age, children may learn names as labels for novel artifact kinds rather than perceptual classes, and that the processes by which they categorize may be mindful and reflective, as in adults.