Abstract
Purpose. Research has suggested that children's ability to perform contour integration of individual elements in the presence of stimulus noise develops slowly (Kàldy & Kovàcs, 2003; Kovács, 2000). A recent study with 3-month-old infants has demonstrated an immaturity in their contour integration mechanisms (Gerhardstein et al., 2004). The goal of this study was to further investigate the developmental trend in infants' ability to integrate individual elements into whole contours. Method. Six-month-olds' discrimination of differently shaped contours was tested via a cueing paradigm in which a circle or square contour, defined by the alignment of oriented Gabor patches, embedded in background noise of randomly oriented Gabor patches, served as a cue for the subsequent presentation of a target on either the right or left. The relation of the contour to background noise called the noise density and defined as the ratio of average noise spacing over contour spacing was set to 1.0. Eye movements were analyzed for correct anticipatory eye movements to the targets in response to which face cue had been presented. Results. Preliminary data indicated that the infants anticipated on 40.1% of trials and 58.1% of those were to the correct target. This percent correct approached but was not significant (p = .0823). Thus, infants were anticipating the targets at chance level, suggesting that they were unable to discriminate the circle and square contours. Conclusions. These data suggest that 6-month-olds' ability for contour integration is not yet mature enough to support discrimination of different shaped contours. Additional data will be collected to examine the effect of noise density level and whether discrimination is possible when no background noise is present. Regardless, the current findings are consistent with the relatively slow maturation of contour integration ability and the underlying neural mechanisms.