Quantitatively Measuring Visual Attention by Analyzing Microsaccades

Abstract

To evaluate the effects of visual attention (VA) on human involuntary miniature eye movements (MEM), we analyzed the microsaccades (MSC), which are components of MEM, under the following three experimental conditions : 1) VA was focused on the foveal object, 2) VA was dispersed in the parafoveal visual field, and 3) VA was focused on one of the parafoveal objects. The results showed that the VA was not focused on the foveal object, the frequency and amplitude of the MSC increased, and the scatter of fixation widened. The results from 2) and 3) showed that the frequency of the MSC was grater in 2) and the mean amplitude of the MSC was similar for both conditions. When VA is not focused, the MSC occur more frequently, and when VA is focused on the foveal object, the amplitude of the MSC reduces. These results suggest that MEM are influenced by VA, and MSC may be used as an indicator of the attentional state. It will be possible to establish whether VA is focused or not on the basis of the analysis of MEM characteristics.