Abstract
Magnitudes of attentional influence on chromatic and achromatic channels were examined using a dual-task paradigm. In experiment 1, the observer should pay attention to rings presented in the central visual field to answer the question about the number of gaps in the rings. This attentional load reduced the sensitivity to chromatic target much but influence to achromatic response was limited. These tendency did not depend on the color of the rings. In experiment 2, chromatic and/or achromatic discrimination tasks were performed in the central and peripheral visual field simultaneously and thresholds were compared to those obtained when the observer pay attention solely to either task. It was found that threshold elevation was prominent when chromatic and achromatic tasks were combined, suggesting that it is difficult to pay visual attention to chromatic and achromatic targets simultaneously.
