Abstract
Vision is a whole-body process involving eye, head, and body movements, so where people look is constrained by the properties of their bodies. We investigated whether developmental changes in locomotor posture—specifically, the transition from crawling to walking—affect infants’ visual experiences.
Thirteen-month-old infants crawled or walked down a 490-cm walkway wearing a head-mounted eye-tracker that recorded their eye movements and field of view. The walkway and opposite wall were covered with regularly spaced stripes. Coders scored videos frame-by-frame to determine the highest and lowest stripes visible in the scene camera, approximating the top and bottom of infants’ visual fields.
Walkers had a better view of distal locations and experienced a richer visual environment filled with people and objects. Walkers could see across the room to the opposite wall 98% of the time, compared to only 78% for crawlers. Thus, for crawlers, the floor completely filled their visual fields 22% of the time. Comparing times when infants could see across the room, walkers could see significantly higher than crawlers (M=138 cm vs. M=66 cm), and were more likely to see their parents and objects in the distance. Conversely, crawlers had a better view of the floor; crawlers could see the floor 99.5% of the time but walkers only 88% of the time. When the floor was in infants’ visual fields, the closest visible point was significantly closer for crawlers than walkers (20 cm ahead of crawlers’ hands vs. 87 cm ahead of walkers’ feet). Therefore, crawlers obtain more visual information about proximal objects and obstacles.
Results indicate that what infants see is intimately tied to body constraints and that infants’ visual world is transformed with changes in locomotor posture. Ongoing analyses are investigating the effects of the shifting visual field on infants’ visual fixations, using gaze calculations from the eye-tracker.
Meeting abstract presented at VSS 2012