The analysis of eye movements can provide rich information about driver's attention and the course of behaviour in hazardous situations. We present data from a driving simulation study showing that the switching between preattentive and attentive processing is reflected in visual fixations. For this initial analysis, we considered fixations from the perspective of their duration and the amplitude of related saccades. Since fixation durations may change instantaneously from one fixation to the next, we further selected the temporal vicinity of the emerging hazard for a closer analysis of fixations around this time. With this second type of analysis, the fixations that actually "detect" a critical event can be discovered and their duration measured. Upon detection of an immediate hazard, there is an increase in fixation duration and a corresponding increase in occurrence of attentive fixations on the cost of preattentive ones. This switching from one level of processing to another is recognisable on a short, phasic time scale. We finally discuss attentional conditions where overlooked or not sufficiently processed hazards do not lead to the appropriate breaking reaction on the part of the driver. (Author/publisher).
Abstract