Free Download Journal "The Role of Object Recognition in Young Infants’ Object Segregation"

New results confirm that young infants draw on experientially derived representations in resolving individuation ambiguities due to shared boundaries between adjacent objects. They extend previous findings in a surprising way: The memory representations that infants draw upon have bound together information about shape, color, and pattern. Our commentary on these important results draws a distinction between two senses of “recognition” and asks in which sense object recognition contributes to object individuation in these experiments. © 2001 Academic Press Key Words: infant cognition; object recognition; object segregation.Sensory input is continuous. The array of light on the retina, even processed up to the level of Marr’s 21/2D sketch (Marr, 1982), is not segregated into individual objects. Yet distinct individuals are provided by visual cognition as input into many other perceptual and cognitive processes. It is individuals we categorize into kinds; it is individuals we reach for; it is individuals we enumerate; it is individuals among which we represent spatial relations such as “behind” and “inside”; and it is individuals that enter into causal interactions and events. Because of the psychological importance of object representations, the twin problems of how the visual system establishes representations of individuals from the
continuous input it receives and the development of these processes in infancy have engaged psychologists for almost a century. Needham’s elegant research program addresses this problem through an examination of early perceptual development. Many researchers have shown that young infants, like adults, draw upon spatiotemporal information—information about the spatial arrangements and motions of visible surfaces—to establish representations of discrete individuals. Two objects separated in space (on the frontal plane or in depth), or moving on spatiotemporally discontinuous trajectories, are resolved into distinct individuals (e.g., Baillargeon , 1991, 1995; Spelke, 1991; Spelke, von Hofsten, & Kestenbaum, 1989; von Hofsten & Spelke, 1985; Xu & Carey, 1996). In her previous work, Needham has shown that by 4.5 months of age, infants also draw upon featural information to resolve ambiguous displays into distinct individuals (Needham, 1998; Needham & Baillargeon, 1997).That is, shown adjacent objects sharing a boundary, such as the box/hose displays in the target article, infants as young as 4.5 months can use dissimilarity of shape, color, and texture to resolve this display into two distinct objects. These results are somewhat fragile at younger ages, as young infants’ performance appears to be highly dependent on the properties of the test objects: Four-and-a-half- montholds fail when the object features are too complex. However, if infants are first exposed to either component of the test array alone for a few seconds, 4.5- to 5- month-old infants can succeed more reliably at this task, looking longer when the objects move in a unitary manner than when they separate into two discrete individual objects (Needham& Baillargeon , 1998; Needham & Modi, 1999). The effects of experientially derived knowledge extend to brief exposures to one of the objects in the infant’s home 24 h earlier.Susan Carey and Travis Williams New York University Needham’s (2001, this issue)DOWNLOAD HERE