Sensitivity measures of visuospatial attention.

Measuring visual sensitivity has become popular to determine the spatial deployment of visual attention. Critically, the accuracy of the measurement depends on the quality of the stimulus used. We evaluated the strengths and weaknesses of six commonly used stimuli for assessing visual attention. While preparing an eye movement to a cued item, participants discriminated a stimulus-specific visual feature, either at the cued location or at other equidistant uncued locations. Stimuli differed in their visual features (digital letters, Gabors, crosses, pink noise, random dot kinematograms, and Gabor streams) and their presentation mode (static or dynamic stimuli). We evaluated these stimuli regarding their temporal and spatial specificity and their impact on saccade preparation. We assessed presaccadic visual sensitivity as a correlate of visual spatial attention and discuss the stimulus-specific time course, spatial specificity, and magnitude of the measured attention modulation. Irrespective of the stimulus type, we observed a clear increase of visual sensitivity at the cued location. Time course, spatial specificity, and magnitude of this improvement, however, were specific to each stimulus. Based on our findings, we present guidelines to select the stimulus best suited to measure visuospatial attention depending on the respective research question.