Tobias Moehler


VSS Best Poster Awards 2014

Effects of visual attention on perceptual and movement performance during saccade preparation

Tobias Moehler, Katja Fiehler; Experimental Psychology, Justus-Liebig-University Giessen, Germany

Previous studies suggest that visual attention is bound to the location of a saccade target during saccade preparation and cannot be withdrawn even when the time to prepare the saccade is extended. However, there is also evidence that attention can be deployed to multiple target locations during the preparation of sequential movements or during the preparation of a movement and a visual discrimination task. Moreover, it is yet unclear whether attentional deployment in space also affects movement parameters. The aim of the present study was to investigate the effects of attentional allocation in space on perceptual and movement performance by employing a modified dual-task paradigm. Participants performed a rapid visual discrimination task at one of three cued locations while preparing a saccadic eye movement to the same location (spatially congruent trial) or a different location (spatially incongruent trial). In addition, saccade preparation time was varied between 0ms and 500ms. Our results showed enhanced perceptual performance in the discrimination task for spatially congruent compared to incongruent trials; however, perceptual performance in incongruent trials was clearly above chance level. Movement preparation time did not affect performance in the perceptual task. Saccade performance, measured by latency, accuracy, and precision, deteriorated in incongruent trials. As expected, saccade latency decreased with increasing movement preparation time. Importantly, for saccadic curvature, a measure which is sensitive to the spatial deployment of attention, we found that saccades curved away from the location of the discrimination target in incongruent trials. Our findings suggest that visual attention is not obligatorily bound to the saccade target, but can be divided upon the discrimination and the saccade target if they appear at different locations in space resulting in costs for perceptual and movement performance.

Acknowledgement: DFG IRTG 1901