Spatial self-reference systems and shortest-route behavior in toddlers.

2 experiments were conducted concerning the development of spatial orientation during the second year of life. Both experiments were focused on oriented search for a hidden target object in the absence of landmarks, which can be accomplished by relating one's movements to knowledge of a target's location. In experiment 1, 18-month-olds were tested to examine the precision with which they use information for the direction and magnitude of self-movement to keep track of the target location. Although the toddlers' search behavior was imprecise, the results showed that they appropriately modulated their search behavior according to the directions and magnitudes of their previous movements away from the hidden target. Experiment 2 was designed to determine whether toddlers can go beyond the information directly experienced in previous routes of travel to infer the shortest route to a hidden target. The results indicated that the 18-month-old and the highly selected 14-month-old subjects can perform spatial inferences of this type. The mechanisms through which these spatial abilities develop are discussed.