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.
Ueno and Uchiyama are with Doshisha University, Kyoto, Japan. Campos and He are with the Dept. of Psychology, University of California–Berkeley, Berkeley, CA. Anderson is with the Dept. of Kinesiology, San Francisco State University, San Francisco, CA. Dahl is with the Dept. of Psychology, University of California–Santa Cruz, Santa Cruz, CA.