The robustness of infant haptic memory: testing its capacity to withstand delay and haptic interference.

The robustness of infant haptic memory was assessed in terms of its capacity to withstand either a brief delay or potential retroactive "interference" from other haptic input. 48 infants (mean age 8 months) were familiarized haptically to a small cube or sphere with smooth or rough surface texture and subsequently tested for recognition of the shape and texture of this stimulus in terms of the relative level of haptic response to 3 test stimuli, comprising the familiar stimulus, a new-shape stimulus, and a new-texture stimulus. The test stimuli were presented (a) immediately, (b) after a 5-min delay, or (c) after a second familiarization or "interference" phase involving another haptic stimulus different in shape and texture to the first. The infants demonstrated recognition of shape and texture in the No Delay condition, of shape and (marginally) of texture in the Delay condition, but only of texture in the Interference condition. The greater susceptibility of shape to interference was considered in terms of the degree of similarity among the shapes employed in the study.