A Shift in Children's Use of Perceptual and Causal Cues to Categorization

The present study explores the ability of 3.5-and 4.5-year-olds to use a causal property (making a machine light up and play music) to build categories of objects, and attach a name to them. First, this use is assessed in the presence or absence of simple perceptual information (color and shape) leading to a conflicting categorization. Second, the role of language is evaluated by varying how the experimenter describes the actions of the objects on the machine. Results show that although children of both ages use causal properties to categorize objects in the absence of conflicting perceptual categorization, older children are more likely than younger children to favor the causal over the perceptual categorization when they conflict. An effect of language was also found with the older children, with explicit causal descriptions of the events enhancing causal categorizations. Finally, a memory probe showed that younger children were likely to misremember causal information when it conflicted with perceptual information. These results suggest that perceptual, linguistic and causal information are all correlated for the younger children, whereas these cues are more independent for the older children. A number of cues can be used to categorize objects. Some of these cues, which we will call simple for the purpose of the present study, are easy to observe and access, and stable in time. Simple cues include perceptual cues such as shape, color and texture. Other cues, which we will call complex, are less easily accessible, more abstract and often relational in nature. For example, some complex cues involve the observation of a particular kind of relation between two entities or phenomena at given times (e.g. functional properties, some causal attributes); others involve some knowledge of a relation between two entities that is usually not observed directly, although such a relation can be revealed through scientific investigation (e.g. genome-to-phenotype relation; categorization based on essence). In the present study, we will be more particularly interested in two complex cues: a linguistic cue (naming), and a novel causal cue (whether a block makes a machine work or not). A question central to the study of infants' and children's categorization is the determination of the kind of cues that are used to categorize objects, and whether and how the different cues are used together. This issue is important because, although there is often a good correlation between different kinds of cues characterizing natural objects (see Gelman & Medin, …