Review of reversal learning data obtained from Ss of various developmental phases suggested that overtraining increases perseveration in pre-school children, and decrease perseveration in older (e.g., 1st grade) children. The present experiment tested this apparent trend. Children of two age groups (X = 4 yrs., 4 mos., vs. X = 6 yrs., 5 mos.) learned a reversal shift after having been trained to a 9 of 10 criterion, or after 20 or 40 additional overtraining trials. The results indicated that overtraining has no effect upon perseveration in the younger children, and increased perseveration in the older children, failing to confirm the apparent development trend. It was also found that criterion-trained younger Ss perseverated more than did criterion-trained older Ss, but that this age difference disappeared in the overtraining conditions. Finally, it was found that ease of overall reversal learning was unaffected by the amount of original training in both age groups. (Author)