Evidence for continuous processing of visual information in a manual video-aiming task

Research shows that individuals are able to correct for an experimentally-induced and unexpected aiming error (i.e., a cursor jump), even when they do not detect it consciously. Researchers have interpreted these results to be evidence of continuous processing of visual afferent information for movement control. The authors conducted 2 experiments to determine whether they would gain additional support for this proposition by showing that correction for a cursor jump can be initiated outside the central visual field. In addition, the authors wanted to determine whether the normally occurring modulation of the ongoing movement is affected by detection and correction of the cursor jump. Participants performed video-aiming movements in which a 30-mm cursor jump occurred in a small proportion of the trials. The results indicate that correction for the cursor jump was initiated when the cursor was as far as 15 degrees of visual angle from the target. In addition, the authors observed accurate corrections when vision of the cursor was withdrawn soon after the cursor jump. Last, online control processes reducing initial movement variability were not significantly affected by the detection and correction for the cursor jump. The results suggest near continuous monitoring of visual afferent information but a more discrete movement-correction process.