SHAKING THINGS UP: YOUNG INFANTS’ USE OF SOUND INFORMATION FOR OBJECT INDIVIDUATION A Thesis by TRACY

Shaking Things Up: Young Infants’ Use of Sound Information for Object Individuation. (December 2007) Tracy Rebecca Smith, B.S., Texas A&M University Chair of Advisory Committee: Dr. Teresa G. Wilcox Object individuation, the capacity to determine whether two perceptual encounters belong to the same object or two different objects, is one of the most basic cognitive abilities and provides a foundation for infants’ understanding of the physical world. Yet very little work has been done to explore infants’ use of auditory information to individuate objects. The first research to investigate infants’ use of sound information to individuate objects was reported by Wilcox et al. (2006), who used a violation-ofexpectation task to examine the extent to which 4.5-month-olds use differences in sound to individuate objects. The results suggested that 4.5-month-olds use property-rich sounds (sounds intimately related to an objects’ physical, amodal properties) but not property-poor sounds (sounds that are more contrived) to distinguish the identity of objects involved in occlusion events. The current study investigated infants’ sensitivity to these two types of sounds within the context of a search task. Three experiments were conducted with infants aged 5 to 7 months. The outcome of these experiments builds and extends on the findings of Wilcox et al. in three ways. First, converging evidence was obtained, using a search task,