Previous manipulative experience in relation to infants' processing of mothers' presentations of objects

Recent work by the present author has identified a sequence of events during joint play of mother and infant which may lead infants to process mothers' presentations of objects in a particular way. This sequence of events implies a special form of detection of discrepancy by infants. The present report is an attempt to determine whether a plausible alternative hypothesis, which also happens to be more parsimonious, can account for previously reported findings which are consistent with the discrepancy hypothesis. The alternative hypothesis states that infants' processing of objects either during mothers' presentations or during infants' independently initiated manipulations is determined by the duration of time infants previously devoted to manipulating the object. The findings contradict this alternative hypothesis, and in so doing, lend further support to the discrepancy hypothesis originally proposed.