Discrepancy detection and developmental changes in attentional engagement in infancy

The processing of discrepancies in visual arrays is fundamental to basic visual processes such as figure-ground segregation and object recognition. In six experiments, we examined this function in 3-and 5.5-month-olds. In Experiment 1, 5.5-month-olds detected a textural discrepancy induced by changes 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 discrepancies versus those that detect discrepancies in relations among features. Experiments 2, 3A, and 3B suggested that, unlike in the case of 3-month-olds in prior studies, textural and singleton discrepancies in arrays that 5.5-month-olds detect do not hold their attention in the presence of other attention-seeking cues. A comparison of the performance of 3- and 5.5-month-olds in Experiments 4A and 4B confirmed the presence of this developmental change. Altogether, these results indicate that infants' detection of color and shape textural discrepancies is consistent with models of adult visual processing that posit a preattentive system for processing features and a resource-demanding attentional system for processing relations among features. They also suggest that the ability to disengage attention from a discrepancy and deploy it at another location develops between 3 and 5.5 months of age.