Sara E Schroer¹ (), Mary Hayhoe¹; ¹University of Texas at Austin

During natural walking, adults adapt their gaze and gait in response to the environment. On rough terrains, adults look at the ground close to their bodies, slow down, and take shorter steps. On all terrains, however, adults often use recent visual information (acquired <1.5s before a step) to guide walking. This information decay rate has been demonstrated across many motor tasks. In our study, we examined whether young children use a similar strategy. 3- through 5-years-old children wore a head-mounted eye tracker while walking on three terrains: a Sidewalk, Stones (an unstable surface), and a narrow Wall. On the Sidewalk, only 31% of looks were on the path and these were an average of 3.9 steps ahead. Children’s cadence was 2.4 steps/s, which suggests they may be acquiring information ~1.6s in advance. On the challenging terrains, the proportion of fixations directed towards the path dramatically increased (82% on the Stones, 79% on the Wall; p’s<0.001). Children looked closer to their bodies on the Stones (2.8 steps ahead) and the Wall (3.2 steps ahead; p’s<0.001). On the Stones, children took shorter steps (p=0.03) and decreased cadence by 10% (p<0.001). Gait changes on the Wall varied – half of the children increased step length by 10.5% and cadence by 12.6% (p’s<0.001); one third decreased step length by 14% (p<0.001), but did not change cadence; and the remaining children did not change their gait. When children deviated from normal cadence – slowing down on the Stones or speeding up on the Wall – they looked ~1.3s in advance. Children who did not change cadence on the Wall looked ~1.4s in advance. These results suggest that children may need more recent information to guide waking on challenging terrains. As with adults, they flexibly adapt their behavior, but doing so requires different information for planning.

Acknowledgements: NIH R01 EY05729 and T32 EY021462