Research in the past decades has investigated the time course of the acquisition of physical knowledge in early development in much detail. However, few is known about the motives that actually lead infants to interact with the objects of their physical world. The research presented here investigated in two experiments if 11-month-old infants'…

Reviews examples from the recent psychological literature relating to object orientation and constancy. The conclusion is reached that the attempt to separate the constancy and discrimination questions in an experimental design employing only a single dependent variable fails practically and theoretically. A theoretically more acceptable…