Infants' means-end search for hidden objects in the absence of visual feedback

Infants beyond 8 months of age typically succeed in search tasks that require them to sequence multiple-stage, means-end actions. However, it is unclear whether infants depend upon visual feedback of limb movements and their consequences during search. We examined whether means-end search is dependent upon visual feedback by testing 8.5-month-olds' ability to uncover and retrieve objects in the dark. Sound was used to direct infants' initial responses toward a covered object, but was terminated as soon as they opened the cover, forcing them to execute the second stage of the search behavior with no further feedback. An additional manipulation involved presenting 'no-toy' trials in the dark or 'surprise' trials, on which the toy was surreptitiously removed after the lights had been extinguished. infants successfully retrieved the toy on dark trials, albeit less frequently than in the light. The organization of their means-ends behavior in the dark was highly similar to that in the light, in terms of the number of reaches made on each trial, the accuracy of their reaches, and the latency to respond before and after opening the cover. Infants were just as likely to search on dark trials with and without a toy, suggesting that infants failed to notice or did not consider the implications of no toy put under the cover. The ability of infants to perform the relatively complicated, means-end search in the dark suggests that this sequential behavior can be carried out on the basis of the infant's memory of the covered object and the actions necessary to achieve the goal.