Relations between uniform connectedness, luminance, and shape similarity as perceptual organizational cues in infancy

Although several studies have examined infants' sensitivity to perceptual organizational cues, few have examined the functional relations among these cues. We examined how uniform connectedness (UC) functions in relation to shape and luminance similarity. UC has been characterized as the entry-level mechanism of perceptual organization and would therefore be predicted to be more salient than the other two cues. We found that UC was more salient than shape similarity organization was, to the point that 6- to 7-month-old infants failed to even organize on the basis of shape in the presence of UC. Luminance similarity, however, was more salient than UC, even though UC was detected by infants in the presence of luminance cues. We conclude that UC is not necessarily the most salient mechanism of perceptual organization in infancy. Moreover, the luminance-UC-shape salience hierarchy exhibited by 6- to 7-month-olds in the present study is consistent with the order of development of sensitivity to these organizational cues.