Development of adaptive constraints in infants' perception of form-function correlations

The course of infants’ cognitive development does not always follow a nonmonotonic, steadily increasing trajectory whereby improvement is defined by infants’ expanding repertoire of abilities. In some cases, for example, their range of abilities narrows with development and is seen as an adaptive process. The purpose of the present study was to gain a better understanding of infants’ developing “adaptive constraints” on their processing of correlations between the appearance and function of features on an object. Fourteen-, 16- and 18-month-old infants were tested in a habituation experiment to investigate the developmental differences in infants’ sensitivity to three correlations: (1) within-feature form-function correlation (the appearance of a particular feature on an object and its function), (2) betweenfeature form-function correlation (the appearance of a feature and the function of a different feature on the same object), and (3) form-form correlation (the appearance of the two features on the same object). Using a between-subjects design, previous research has shown that 14-month-olds are sensitive to both within- and betweenfeature correlations whereas 18-month-olds are constrained and sensitive only to the within-feature form-function correlation (Madole & Cohen, 1995). The present study included three important changes to this previous research: (1) infants were tested on a form-form correlation in addition to the two form-function correlations, (2) infants were tested using a within-subjects design rather than between-subjects, and (3) in addition to testing 14- and 18-month-olds, 16-month-olds were also studied. It was found that 18-month-olds showed sensitivity only to the withinfeature form-function correlation; whereas the 14- and 16-month-olds showed sensitivity to none of the correlations. These results are interpreted as evidence that because they are without constraints, the younger two groups of infants struggled with attending to all the information presented at once; whereas that the oldest group of infants benefited from their adaptive constraint to process only the within-feature form-function correlation. These findings have implications for our understanding of the development of constraints on infants’ processing of information as well as the methods used to study infants’ sensitivity to correlations.