Discrepancy detection and developmental changes in attentional engagement in infancy

The processing of discrepancies in visual arrays is fundamental to basic vi sual processes such as figure-ground segregation and object recognition. In six experiments, we examined this function in 3-and 5.5-month-olds. In Exp eriment 1, 5.5-month-olds detected a textural discrepancy induced by change s in individual color and shape features but not one induced by changes in relations among these features. These results suggest that, in infancy, as in adulthood, there are differences in the processes that detect featural d iscrepancies versus those that detect discrepancies in relations among feat ures. Experiments 2, 3A, and 3B suggested that, unlike in the case of 3-mon th-olds in prior studies, textural and singleton discrepancies in arrays th at 5.5-month-olds detect do not hold their attention in the presence of oth er attention-seeking cues. A comparison of the performance of 3- and 5.5-mo nth-olds in Experiments 4A and 4B confirmed the presence of this developmen tal change. Altogether, these results indicate that infants' detection of c olor and shape textural discrepancies is consistent with models of adult vi sual processing that posit a preattentive system for processing features an d a resource-demanding attentional system for processing relations among fe atures. They also suggest that the ability to disengage attention from a di screpancy and deploy it at another location develops between 3 and 5.5 mont hs of age.