Effects of visual and conversation tasks upon a functional visual field while driving

Effects of visual task and/or conversation task on functional visual field (FVF) during driving was studied experimentally. Red or pink circular target was briefly presented somewhere on a movie scene from driver's view in a car following situation, and the observer's task was to indicate the target position. The visual task loaded on the observer was to read out the two alphabet letters presented in the center of the visual field. The conversation task was to answer an easy question orally. The FVF narrowed with the visual task as well as with the conversation task, while it markedly shrinked when both visual and conversation task were imposed simultaneously.