Infants show a dramatic shift in postural and emotional responsiveness to peripheral lamellar optic flow (PLOF) following crawling onset. The present study used a novel virtual moving room to assess postural compensation of the shoulders backward and upward and heart rate acceleration to PLOF specifying a sudden horizontal forward translation and a sudden descent down a steep slope in an infinitely long virtual tunnel. No motion control conditions were also included. Participants were 53 8.5-month-old infants: 25 prelocomotors and 28 hands-and-knees crawlers. The primary findings were that crawling infants showed directionally appropriate postural compensation in the two tunnel motion conditions, whereas prelocomotor infants were minimally responsive in both conditions. Similarly, prelocomotor infants showed nonsignificant changes in heart rate acceleration in the tunnel motion conditions, whereas crawling infants showed significantly higher heart rate acceleration in the descent condition than in the descent control condition, and in the descent condition than in the horizontal translation condition. These findings highlight the important role played by locomotor experience in the development of the visual control of posture and in emotional reactions to a sudden optically specified drop. The virtual moving room is a promising paradigm for exploring the development of perception–action coupling.
Moeko Ueno, Ichiro Uchiyama, Joseph J. Campos, David I. Anderson, Minxuan He and Audun Dahl
David I. Anderson, Audun Dahl, Joseph J. Campos, Kiren Chand, Minxuan He and Ichiro Uchiyama
This report describes a novel test of the prediction that locomotion-induced changes in an infant’s functional utilization of peripheral lamellar optic flow (PLOF) for postural stability contributes to avoidance of the deep side of a visual cliff. To test the prediction, a corridor, with either low-textured or high-textured walls, was constructed to run the length of a visual cliff. The infants, 9.5-month-olds with varying amounts of hands-and-knees crawling experience, were randomly assigned to the low-texture (n = 30) or the high-texture condition (n = 32). Consistent with predictions, the findings revealed significant interactions between crawling experience and texture condition for the probability of crossing and the latency to venture onto the deep side of the cliff. Most notably, more experienced crawlers, but not less experienced crawlers, were significantly more likely to cross the visual cliff to the parents and ventured onto the cliff faster in the high-texture condition than in the low-texture condition. The availability of PLOF thus had an effect on infants’ crossing behavior on the visual cliff. We interpret these findings as evidence for a three-step process in which locomotor-induced changes in visual proprioception play a central role in the development of wariness of heights.