Development of allocentric spatial memory abilities in children from 18 months to 5 years of age.
To assess the development of accurate spatial memory and its relationship to organized search strategies, children (18-71 months old) and college students searched for rewards hidden at the ends of the arms of an eight-arm radial maze. Subjects made their first four choices in random order selected by the experimenter (forced choice) or in whatever order they wished (free choice). In some conditions, a retention interval was imposed between arm choices 4 and 5, followed by a resumption of the task. With free choice, accuracy of spatial memory increased linearly with age, and the proportion of tests on which the child entered four adjacent arms in sequence during the first four choices, a measure of organized searching, also increased linearly with age. Disrupting this sequential search strategy (forced choice) reduced accuracy for both children and college students, although the reduction with college students was small. Delays had minimal effects for children who met criterion at 0-delay and for college students. Although response patterns seem unimportant in accurate spatial memory in rats, systematic search strategies mature together with, and probably contribute to, the improvement of spatial memory with age in humans.