How Moving Backgrounds Influence Interception

Abstract

Reaching movements towards an object are continuously guided by visual information about the target and the arm. Such guidance increases precision and allows one to adjust the movement if the target unexpectedly moves. On-going arm movements are also influenced by motion in the surrounding. Fast responses to motion in the surrounding could help cope with moving obstacles and with the consequences of changes in one’s eye orientation and vantage point. To further evaluate how motion in the surrounding influences interceptive movements we asked subjects to tap a moving target when it reached a second, static target. We varied the direction and location of motion in the surrounding, as well as details of the stimuli that are known to influence eye movements. Subjects were most sensitive to motion in the background when such motion was near the targets. Whether or not the eyes were moving, and the direction of the background motion in relation to the direction in which the eyes were moving, had very little influence on the response to the background motion. We conclude that the responses to background motion are driven by motion near the target rather than by a global analysis of the optic flow and its relation with other information about self-motion.

Aging and Sensitivity to Illusory Target Motion With or Without Secondary Tasks

“…An infrared emitting diode (IRED) was placed on the participant's right index finger and was tracked at 500 Hz by an Optotrak (Northern Digital, Waterloo, ON, Canada). Taps were detected using a threshold deceleration of 50 m/s 2 , which has proven to be a very reliable method (Brenner and Smeets, 2015). Auditory stimuli were presented to the participants by a computer situated to their right.…”

“…Vision guides goal-directed reach movements towards moving targets (Brenner and Smeets, 2015;Brouwer et al, 2002Brouwer et al, , 2003Kavcic et al, 2011). When judging the target's motion, one could simply rely on the target's retinal slip together with extra-retinal information about eye, head and body movements, but one might be able to improve the precision by assuming that the environment is stable.…”

Eye movements in interception with delayed visual feedback

“…One may wonder whether the way people direct their eyes is only aimed at increasing the visual resolution (Bock 1993; Prablanc et al. 1979) and improving velocity judgments (Brenner and Smeets 2011, 2015; de la Malla et al. 2017), or whether it is also easier to guide the hand towards where one is looking (Ballard et al.…”

A simple interception task used as diagnostic tool of multisensory integration problems in aging

“…Finally, we examined susceptibility to a second influence of moving the background: a tendency to temporarily move in the same direction as the background if the background abruptly starts to move when the arm movement is already underway. This effect does not depend on the direction of target motion or whether the target is moving at all (Brenner and Smeets, 1997;Saijo et al, 2005;Brenner and Smeets, 2015). In our experiment, such background motion would give rise to a deviation in the opposite direction than that caused by a background that is moving when the target appears.…”

“…Vision guides goal-directed reach movements towards moving targets (Brouwer et al, 2002;Brouwer et al, 2003;Kavcic et al, 2011;Brenner and Smeets, 2015). When judging the target's motion, one could simply rely on the target's retinal slip together with extra-retinal information about eye, head and body movements, but one might be able to improve the precision by assuming that the environment is stable.…”