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L G Craton

Publications and source records attributed to L G Craton.

5 recordsLinked to original sources
PubMed1996

The development of perceptual completion abilities: infants' perception of stationary, partially occluded objects.

We explored infants' ability to perceive stationary, partially occluded objects as connected units (Experiments 1 and 2) with specific appearances (Experiment 3). In each experiment, the infants saw 2 test events involving what appeared to adults to be a tall rectangular object whose middle portion was hidden behind a narrow screen. During the test events, the screen alternately uncovered and covered the object. In Experiments 1 and 2, removal of the screen revealed either a single, connected rectangle (complete object event) or an interrupted rectangle with a gap where the screen had been (broken object event). In Experiment 3, removal of the screen revealed either a rectangle (rectangle event) or a cross-shaped object (cross-shape event). The pattern of infants' looking times at these events suggest that they perceive the unity of the partially occluded object by 6.5 months of age but did not perceive the form of the hidden part of the object until 8 months. The results of baseline control conditions support this interpretation.

Adult↗
PubMed1990

Kinetic occlusion: further studies of the boundary-flow cue.

Previous work has demonstrated that human beings employ a processing assumption, the boundary-flow constraint, in perceiving the order of depth at an edge. Subjects perceive depth order of surfaces on the basis of the relative motions of an image boundary and a projected surface texture on either side of the boundary. In the present study, adult subjects viewed computer-generated kinematograms in which boundary-flow information provided the only cue for depth order. The results of Experiments 1 and 2 indicate that common motion between boundary and texture and differential motion between boundary and texture can independently generate the perception of ordered depths of surfaces. In Experiment 3, we examined the interaction of two processes involved in the extraction of depth order from boundary-flow displays: (1) the propagation of foreground and background surfaces from texture to boundary; and (2) the computation of depth order of surfaces on either side of the boundary. The results indicate that while the mechanism that computes depth from boundary-flow information functions reliably when the mean distance between texture and boundary is 8.1(0), surface propagation may be disrupted for distances of this magnitude.

Adult↗
PubMed1990

Children's use of frames of reference in communication of spatial location.

The frames of reference used by 4-, 6-, and 8-year-old children were studied in a spatial direction-giving task. Children were asked to specify verbally the location of a toy hidden under one of several identical cups. The child and listener sat facing each other at opposite ends of a room that had distinctive or nondistinctive landmarks proximal and distal to the hiding location. Location needed to be specified with respect to either the left-right dimension, the front-back dimension, or both. The results indicated that (1) although children's overall performance improved with age, communication about the left-right dimension was particularly difficult for 4-year-old children and showed a higher rate of improvement with age than communication about the front-back dimension; and (2) the frames of reference that children incorporated into their directions changed with age and differed for directions about the front-back and left-right dimensions. Both 4- and 6-year-old children used person references (themselves or the listener) to specify front-back relations, but only the 6-year-olds were able to compensate for their apparent difficulty in using the terms left and right by using landmarks to specify the left-right dimension. Eight-year-olds used a combination of person and landmark references in directions about both dimensions. Discrepancies between the frames of reference children used to communicate spatial location and those typically used in other spatial cognition tasks are discussed in terms of developmental and task constraints.

Attention↗
PubMed1988

Infants' sensitivity to boundary flow information for depth at an edge.

We investigated infants' sensitivity to a recently discovered kinetic depth cue, boundary flow. 5-month-old infants viewed computer-generated displays in which the relation between the motion of a boundary, indicating an edge, and 2 regions of dots on either side of the boundary, indicating surfaces, provided the only information specifying the order of the 2 surfaces in depth. Infants showed a significant reaching preference for the apparently nearer region of the display. Since previous research has demonstrated that infants reach more frequently for the nearer of 2 surfaces, this result indicates that 5-month-old infants are sensitive to boundary flow information for depth at an edge.

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