Perception of visual speed while walking

Every time we move through our environment, our own movements make the image of the world move on our retinae. In addition, moving objects produce retinal image motion as well (provided we don’t follow them with our eyes). How does our brain know which retinal image motion is produced by our own movements and which by actual motion of objects in the world around us? Does the perceived speed of moving objects change when we walk, compared to when we’re standing still? According to recent studies, perceived visual speed slows down when we walk (Durgin et al., 2005). This has been explained as an adaptive change in speed coding, caused by an automatic subtraction of part of the walking speed from the retinal image speed (Durgin & Gigone, In press). Currently, we are studying how general this phenomenon is. First results suggest that the reduction in perceived speed during walking may depend on the visual speed itself: it seems to be stronger with slower visual speeds. Our aim is to investigate this phenomenon more extensively and to describe the findings in a quantitative model, incorporating the different sensory signals that may play a role (visual, vestibular, proprioceptive, motor commands).
Last updated: Tuesday, 07.05.2013