Effect of attention at high temporal frequencies

Abstract

[Purpose] To investigate how attention influences visual processing of high temporal frequency stimuli, we measured contrast sensitivity to luminance flicker of a moving target with and without knowledge of the location of the stimulus. [Experiment] We used circular moving disks around the fixation point as stimuli. The luminance of one of the disks (target disk) modulated temporally at a time about the middle of 4s stimulus movement. The observer responded whether the modulation was visible or not after the termination of the stimulus. Repeating the judgment with variable contrast modulation, contrast threshold was determined by a staircase procedure. The target disk was cued before the trial in one condition (cue condition) while no cue was presented in the other condition (no-cue condition). To examine whether the knowledge of the target influences the contrast sensitivity, threshold was compared between the conditions. [Results] Contrast sensitivity was higher in the cue condition than in the no-cue condition at temporal frequencies around 8 Hz when disks was moving at 0.33 round/s, although sensitivity was similar in both conditions for stationary disks. Knowing the target and tracking it increased sensitivity to temporal contrast modulation. [Discussion] The results suggest that attending to the moving target increases sensitivity to stimulus flickering. Attention is suggested to play a role in processing of high temporal frequency stimulation.

Footnotes

 Supported partially by Tateishi Science and Technology Foundation