Rate of habituation and visual memory in infants.

This study investigated 17-week-old infants' response to discrepancy as a function of rate of habituation. 36 subjects were repeatedly shown a pattern containing 4 geometric shapes until they reached a proportional criterion of habituation: each infant's fixation time had to decrease by at least 50%. On the basis of 2 nonoverlapping distributions of trials to criterion, fast and slow habituators were identified. Recovery of fixation time was found for both fast and slow habituators when a discrepant stimulus was presented following habituation. These data were interpreted as reflecting developmental differences in encoding. After several interpolated trials with the new pattern, the infants' response to the original habituation stimulus increased, suggesting that the interpolated trials had interfered with their memory for the habituation stimulus.