Working memory in infancy: six-month-olds' performance on two versions of the oculomotor delayed response task.

The capacity of 6-month-old infants to maintain information in working memory for several seconds was studied using two versions of an oculomotor delayed response task. Infants were presented with either a cue stimulus in a target location (Experiment 1), or an abstract, central stimulus (Experiment 2) which could be used to predict the peripheral location in which an attractive target stimulus subsequently appeared. Eye movements during delay periods from 600 to 5000 ms were recorded. The results indicated that infants maintained information about stimulus locations in working memory for 3-5 s. These results imply maturity of regions of the prefrontal cortex closely associated with a similar task used in neurophysiological and neuroimaging studies.