The Effect of Exogenous Temporal Attention on the Gradient of Spatial Attention

Abstract

The gradient model of spatial attention states that resources of attention are concentrated in the center of focus and gradually decrease as we move our attention away from the center. Previous studies indicate that triggering temporal attention can significantly improve the subjects’ overall performance in attention tasks. In this study, we aim to investigate the effects of temporal attention on the distribution of spatial attention over increasing distance. In our task, two types of trials are presented to the subjects, Rhythmic and Arrhythmic. In rhythmic trials, temporal attention is evoked using an auditory rhythmic cue that indicates the onset of the targets' appearance. In all of the trials, spatial attention is engaged by a circular cue appearing at 7 degrees of visual angle from the fixation cross. Targets are presented at 9 degrees of visual angle in one of five possible distances from the cue. We compared the performance of our subjects in the rhythmic and arrhythmic trials over our various distances. We found that temporal attention significantly improves the reaction time of the correctly answered trials in all distances. Moreover, consistent with the gradient model, the performance gradually decreases as the target moves further from the cue in arrhythmic trials. More interestingly, in rhythmic trials, the participants show the best performance in the third (middle) distance from the cue, and it gradually worsens, as we move away from the middle distance. To be more specific, in rhythmic trials, the gradient model is still noticeable; However, the center of attention is dislocated from the closest position to the middle position from the spatial cue. Consequently, in rhythmic trials, the distance between the fifth (furthest) position and the center of attention is divided in half, which results in maintaining a relatively high performance among all distances.