Locomotor status and the development of spatial search skills.

The principal objective of this experiment was to investigate whether previous reports of a relation between locomotor status and stage 4 object permanence performance generalized to performance on a different object localization task. A secondary objective was to evaluate the contribution of visual tracking as a mediating variable in the relation between locomotor experience and search performance. Precrawling (n = 20), crawling (n = 10), and creeping (n = 18) infants (M = 33 weeks old) were tested using a search task in which either they or the hiding containers were rotated 180 degrees before search was permitted. The results revealed that locomotor status was related to search performance following a displacement of the infant, but not following a displacement of the containers. Moreover, visual tracking of the correct container was not related to locomotor status, even though it was related to search performance. These findings suggest that the effects of locomotor experience on infants' search performance are quite specific and are mediated by a variety of factors that do not necessarily generalize across search tasks.