Object representation and predictive action in infancy

Previous research has shown that 6-month-old infants extrapolate object motion on linear paths when they act predictively on fully visible moving objects but not when they observe partly occluded moving objects. The present research probed whether differences in the tasks presented to infants or in the visibility of the objects account for these findings, by investigating infants' predictive head tracking of a visible object that moves behind a small occluder. Six-month-old infants were presented with an object that moved repeatedly on linear or nonlinear paths, with an occluder covering the place where all the paths intersected. The first time infants viewed an object's motion, their head movements did not anticipate either linear or nonlinear motion, but they quickly learned to anticipate linear motion on successive trials. Infants also learned to anticipate nonlinear motion, but this learning was slower and less consistent. Learning in all cases concerned the trajectory of the object, not the specific locations at which the object appeared. These findings suggest that infants form object representations that are weakly biased toward inertial motion and that are influenced by learning. The findings accord with the thesis that a single system of representation underlies both predictive action and perception of object motion, and that occlusion reduces the precision of object representations.