Spatial memory in preschool infants.

In order to test the spatial competence of preschool infants, two groups, aged 2 years and 4 years, were tested on a version of the "radial maze" task. They were required to obtain a chocolate sweet from each of eight identically labelled positions in an unfamiliar room. Four-year-olds accomplished this with considerable accuracy, rarely revisiting previously sampled positions. Two-year-olds performed marginally above chance. Variants of the task were employed, including rotation of the room configuration so that labelled positions were rendered ambiguous with respect to all other environmental stimuli. The latter caused a marked fall in performance in those infants that had been scoring above chance. By these criteria, infants clearly possess a form of intuitive "spatial memory" that is likely to mature during the second and third years. Parameters of performance were remarkably similar to those seen in comparable studies with nonhumans. It is likely that hippocampal development in early infancy underlies this evolving skill, assuming cross-species similarity in the organization of spatial behavior, and that locomotor competence is required for its development.