Abstract
A critical task for vision is to represent objects as the same persisting individuals over time and visual change. How is this accomplished? Across several areas of cognitive science, perhaps the most important principle is thought to be cohesion: objects must maintain single bounded contours. Infants, for example, fail to represent complex stimuli that undergo cohesion violations, such as pouring sand, as persisting individuals. Here we explore the role of cohesion in object persistence by examining such violations in their simplest form: a single object splitting into two. We first demonstrated a role for cohesion in adults' visual perception, by showing that splitting (but not similar control manipulations) yields severe performance costs in ‘object reviewing’ tests of persistence (Mitroff, Scholl, & Wynn, 2004, Psych. Sci.). To explore whether such simple cohesion violations affect infants' perception of persisting objects, we used a forced-choice crawling task with 10- and 12-month-olds. In the control condition, infants were shown one cracker hidden in one location and two crackers hidden in a second location. In the splitting condition they were shown a single cracker hidden in one location and then a larger cracker split into two, with the two resulting pieces hidden in a second location. Infants selectively crawled to the two-cracker location in the control, but they failed to do so in the splitting condition. Even though both conditions involved the same ultimate presentation of one vs. two crackers, the infants were unable to represent the two crackers as ‘more’ when they resulted from a ‘split’. Together, these results with adults and infants suggest that even simple cohesion violations play a key role in the representation of objects as persisting individuals.
SRM was supported by NIMH #F32-MH66553-01. BJS & KW were supported by NSF #BCS-0132444