Infant Perception of Object Unity from Translatory Motion in Depth and Vertical Translation

Abstract

Previous research indicated that 4-month-old infants perceive the unity of a center-occluded object when its visible ends share a common lateral translation in space. The present work investigated the class of motion relationships that can specify object unity to infants, specifically, asking whether it includes all rigid translations. 3 experiments tested the informativeness of 2 axes of translation not previously studied: translation in depth and vertical translation. These motions also allowed assessment of certain interpretations of previous results that invoke specific sensory consequences of lateral movement, rather than perceived motion, as underlying perceived unity. Experiment 1 provided evidence that a small extent of translation in depth specified the unity of an object, but only to the subgroup of infants who detected the motion. Experiment 2 used a greater displacement in depth and found clear evidence for perception of object unity. Experiment 3 indicated that vertical translation, in which the 2 visible areas of the partly hidden object undergo dissimilar changes, also specifies object unity to infants. These results suggest that infants' perception of object unity depends on perceived coherence of motion, no matter how specified, and that the class of informative motions includes all rigid translations.

Perception of Kinetic Illusory Contours by Two‐Month‐Old Infants

“…Neonates can perceive luminance-defined edges, even with relatively poor visual resolution (see Slater, 1995), but several lines of research point to restrictions in young infants' ability to organize stationary information into coherent percepts of occlusion. First, Kellman and Spelke (1983; see also Jusczyk et al, 1999) reported that 4-montholds failed to perceive the unity of a partly occluded rod when it was stationary, but perception of object unity was especially reliable when the rod moved (Johnson & Aslin, 1995, 1996Kellman, Spelke, & Short, 1986). The earliest age at which infants have been found to perceive the unity of a stationary partly occluded object is 6.5 months (Craton, 1996).…”

Spontaneous object and movement representations in 4-month-old human infants and albino Swiss mice

“…Baillargeon, 2004). Motion in particular is interesting because in many situations, it signals to infants the presence of events better than space does (Kellman, Spelke, & Short, 1986;Werker, http://dx.doi.org/10.1016/j.cognition.2014.12.010 0010-0277/Ó 2015 Elsevier B.V. All rights reserved. Cohen, Lloyd, Casasola, & Stager, 1998): it determines whether objects are animate or inanimate, and may be the basis for understanding the causality of events (Golinkoff, Harding, Carlson-Luden, & Sexton, 1984;Kotovsky & Baillargeon, 2000;Mandler, 2004;Wang, Kaufman, & Baillargeon, 2003).…”

“…However, because movement is so central to young infants' perception of objects, it has primarily been used as a tool for studying object properties (see Baillargeon, 2004). Movement thus facilitates object perception during the first months of life (Kellman et al, 1986;Smith, Johnson, & Spelke, 2003;Werker et al, 1998): young infants fail to perceive objects both if these are stationary (Kellman & Spelke, 1983), and if the infants themselves are moving relatively to a stationary object (Kellman, Gleitman, & Spelke, 1987). This suggests that object movement, and not any motion in general, may be necessary for young infants to perceive objects.…”

Learning to perceive object unity: a connectionist account

“…two rod parts) that extend from behind a nearer, occluding box (Figure 1a). Kellman and Spelke (1983;Kellman, Spelke & Short, 1987) found that after habituation to a display in which the two surfaces underwent common motion behind a stationary occluder (reported by adults to consist of a single object behind an occluder), the infants looked longer at two disjoint rod parts (a 'broken' rod; see Figure 1b) than at a single, complete rod ( Figure 1c). Given infants' tendency to look longer at novel relative to familiar stimuli after a period of habituation (Bornstein, 1985), this result suggests that these infants perceived the rod surfaces in the habituation display as occupying a single, partly occluded object.…”