Modulation of manual activity by vision in human newborns.

This experiment investigates neonatal intersensory functioning between touch and vision for texture density. The experiment compared manual activity (holding time and hand pressure frequency) recorded on objects in the presence (test period) or absence of visual information (pre-test and post-test periods). Thirty-two babies were assigned to four experimental conditions according to texture density of the objects held and seen during the test period: Objects had either the same (matching conditions) or different (mismatching conditions) texture density information. The results clearly showed that in matching conditions, holding times were systematically increased during the test period. However, hand pressure frequency remained unchanged over the three test periods. In the mismatching conditions, holding times remained unchanged over the three test periods. However, hand pressure frequency systematically changed during the test period according to the texture density of the visual object. These results indicate newborns' capability to compare texture density information across modalities. Copyright 2001 John Wiley & Sons, Inc.