The Effects of Motion on Position Representations for Perception and Action
- Author(s): Kosovicheva, Anna
- Advisor(s): Whitney, David
- et al.
Accurately perceiving the locations of objects is essential for successfully interacting with our environment. However, the visual system must constantly contend with motion, both from objects moving through space and on the retina as the observer moves through the environment. Previous work has shown that motion can bias the perceived locations of both moving and non-moving targets, demonstrating that the visual system uses information from motion to update the represented locations of objects. Here, we examined the extent and circumstances under which motion-induced position shifts can influence perception, and whether they can influence action. First, we used psychophysics to demonstrate that motion can influence the location at which low-level adaptation is observed, supporting the idea that motion can bias retinotopic coding of stationary objects at early stages of visual processing. Moreover, we demonstrate that motor responses are not immune to these early influences of motion on position representation. Specifically, we show that position shifts resulting from motion can bias saccade targeting. However, this influence of motion-induced position shifts on saccade targeting does not simply result from perceptual shifts in position. Instead, we demonstrate that the saccade system updates information from motion-induced position shifts before observers are able to consciously perceive these changes. Together, these experiments support the idea that motion exerts an early influence on represented positions and that the saccade system has access to this information before it is perceptually registered.