The theory of perceptual narrowing suggests that as the level of demand increases at the fovea, there will be a corresponding decrease in the visual area around the fovea from which peripheral information can be extracted. This theory has important implications for driving as peripheral information is necessary for directing attention to potential hazards, yet it suggests that degradation of the peripheral field occurs when we need it most. This study aimed to explore the nature of perceptual narrowing in the driving domain. As novice drivers are believed to suffer higher levels of cognitive demand than more experienced drivers, experience was included as a factor to investigate whether the effect of increased demands upon peripheral target detection rates would differ between the two groups. A series of video clips taken from the driver's perspective were shown to subjects whose primary task was to actively view the clips as if they were the driver, searching for potential hazards while their eye movements were monitored. A secondary task required them to respond to briefly presented, peripheral targets. Hit rates were calculated according to the current level of clip demand when each target was presented and according to onset eccentricity (distance from the current fixation to the target when it appears). Results revealed main effects of both demand and eccentricity, which argue for a general interference model of perceptual narrowing, though a strong effect of experience was not found. (A)
Abstract