Abstract: To study the mechanisms underlying orienting of attention in visual space, an experiment was designed to test the effect of a peripheral cue(brightening of one of three dots with 4° eccentricities) on the discrimination of targets with different eccentricities(2°, 3°, 5°and 6°). The results showed that the peripheral abrupt onset captured attention involuntarily and the spatial-temporal characteristics of attention shift was more consistent with the hypothesis of a spotlight model of attention shift than that of a zoom-lens model or a spatial gradient model. Moreover it was found that the attention spotlight needed about 25 ms to move 1 visual degree.

Key words: visual selective attention, automatic process, attention distribution model