Object individuation in infancy: The use of featural information in reasoning about occlusion events

Recent findings by Xu and Carey (1996) indicate that, after seeing two dist inct objects (e.g., a duck and a ball) emerge on the opposite sides of a sc reen, 10-month-olds show no surprise when the screen is removed to reveal o ne (e.g., a duck) as opposed to two objects (e.g., a duck and a ball). The authors took their results to mean that 10-month-olds are unable to use fea tural information to individuate objects. The present research examined a d ifferent interpretation of the results. This interpretation was based on a distinction between event mapping in which infants see a sequence of two di stinct events and judge whether the two are consistent, and event monitorin g, in which infants see a single event and judge whether successive portion s of the event are consistent. The present research contrasted infants' per formances in event-mapping tasks in which they saw first an occlusion and t hen a no-occlusion situation (as in Xu & Carey) and in event-monitoring tas ks in which they saw only an occlusion situation. It was hypothesized that infants would be more likely to give evidence of correct individuation when tested with the event-monitoring as opposed to the event-mapping tasks. Ei ght experiments were conducted with infants ages 7.5 to 11.5 months. These experiments yielded two main findings. First, when tested with an event-mon itoring task, even 7.5-month-olds give evidence that they can use featural information to individuate the objects involved in an occlusion event. Seco nd, when tested with an event-mapping task, even 9.5-month-olds give eviden ce that they can use featural information to interpret an occlusion event a s long as the event is made extremely simple. These findings give weight to the distinction between event mapping and monitoring and more generally be gin to shed light on the fundamental processes involved in infants' formati on and use of event representations. (C) 1998 Academic Press.