Improvement of Visual Attention by Dotted Background Noise

Weak noise in the background is repeatedly reported to improve visual sensitivity remarkably. This sensory effect is known as stochastic resonance, a putative mechanism whereby neural noise arising from background noise can increase signal detection accuracy. Despite many reports on the nerurophysiological and psychophysical effects of stochastic resonance, the study on the cognitive effect is in its infancy. In the present study, we investigated the spatial noise suitable for improving visual attention. Twenty-five college students participated in this study. From a stream of 30 letters in black color was presented in the center of white background screen, the participants were asked to identify two targets. The letters were hiragana and katakana, two syllabaries in the Japanese lettering system that each contain 46 phonograms. The targets were two hiragana letters in 28 katakana letters, or vice versa. The interval between targets was 493ms. A total of 24 streams were presented in each experiment. The targets could be easily identified in a background with 1% noise, compared with other backgrounds that include 3% or no noise. This result indicated that weak background noise could improve visual attention. Visual cognition and attention are controlled by wide regions of the cerebral cortex. The effects of stochastic resonance may be exerted on these brain regions to enhance visual attention.