Amount of training and retention by infants

In studies of animals and adult humans, more training typically leads to better retention. The generality of this finding was assessed in two studies with human infants in which amount of training was manipulated in two different ways. In the first study, 3-month-olds were trained for either 1, 2, or 3 sessions, each 9 min long; in the second, they were trained for a single session that was either 6, 9, 12, or 18 min long. Retention of independent groups was measured after delays ranging from 1 to 21 days. In both studies, different amounts of training did not yield group differences on any of the standard measures of acquisition or after a retention interval of 1 day. After intervals of a week or longer, however, more training led to better retention. Across studies, the long-term retention of groups that were trained for the same amount of time differed. We speculate that subjects learn different things in these two training regimens.