Results of three experiments support the generalization that early perception of object unity depends on perceived motion, and that the class of effective motions includes, at least, the rigid translations of an object in three-dimensional space. Effective motions may be specified by very different sources of stimulus information. (RH)

In contrast with controls and newborn presented with static models, only newborn presented with dynamic models reproduced the models' actions at significant levels. Infants in the static condition fixated the experimenter longer than those in the dynamic one. Results are discussed in terms of neurophysiological findings concerning the control of…