Thinking and driving: how safe?
By: Drivers.com staff
Date: 2000-08-20
How safe is it to think and drive? This was the question posed by a couple of Spanish researchers, Miguel A. Recarte, a psychologist at the Universidad Complutense in Madrid, and Luis M. Nunes, a Spanish government psychologist specializing in driver research.
And while the study, published in the Journal of Experimental Psychology , probably raises more questions than it answers, it does indicate that thinking can be highly distracting to drivers, particularly when it involves visualizing objects.
Seven women and five men, aged 21 to 37, took part in the experiment, which was conducted on roadways near Madrid. None of the 12 was familiar with the car (a Citroen BX-GTI, which the participants were allowed to take on a brief test drive) or the routes (which totaled 52 miles). All the tests were performed in daylight and in dry weather.
The car was equipped with an infrared video system that continuously tracked the participants' eye movements as well as their view of the road. Drivers wore nothing on their heads-no goggles or helmets-that could potentially obscure their view.
The drivers were given both verbal and spatial imagery tasks and the amount of attention needed to solve them was calculated by measuring the amount of dilation in the pupils of their eyes. The verbal task involved repeating groups of words that start with the same letter. The visual and spatial exercise involved imagining individual letters of the alphabet (either as stationary or rotating in space) in order to answer a series of questions.
"In spite of the importance of attention and visual inspection in traffic, research on eye movements as a function of attentional workload while driving is scarce, especially if the type of attentional resources involved is taken into account," the researchers say." Not so long ago, this could be partially explained by the technical complexity of recording eye movements during driving in real traffic without causing great experimental interference with normal driving.
Eyes freeze up during thinking
"In summary," the researchers add, "for fixation duration, an identical pattern was produced on highways and on roads: performing a mental spatial-imagery task produced longer fixations than a verbal task or than ordinary driving. This increment in fixation duration can be described as an eye freezing effect."
The researchers found that the number of glances at various objects in the car such as the dashboard, the speedometer, and the internal and external mirrors decreased when mental tasks were performed.
"With regard to the implications for driving, the spatial reduction of the visual inspection window, including the reduction of the inspection of mirrors, could be interpreted as a predictor of decreased probability of detecting traffic events, particularly when performing mental spatial-imagery tasks," the researchers say.
"However, considering the limitations of interpreting eye movements in terms of attention, this cannot simply be assumed. The issue of whether the narrowing of the visual inspection window causes loss of peripheral visual capacity and visual information processing (peripheral or otherwise) remains open.
"Practically speaking, such visual concentration may be no worse than driving with dispersed attention and gaze (landscape, vehicles, houses, etc.). A more direct demonstration is necessary to discover whether events occurring in the visual periphery while driving are more poorly detected when performing a mental task or whether information (peripheral or otherwise) is more poorly processed when performing a task.
"On the one hand, any reduction of information availability can be interpreted as a higher risk level. On the other hand, this is only true if, while driving normally, all our attentional resources are focused on relevant driving information so that any reduction in visual processing would imply less availability of this information.
"Do all fixations on the road represent relevant information processing? While looking at the road scenario, there is a lot of information that is irrelevant in a specific driving context or situation. When observing a reduction of the inspection of speedometer or mirrors or of the functional visual field, we do not know whether the eliminated glances correspond to relevant or irrelevant information, as far as road safety and optimization of the driving strategy are concerned."
From a practical point of view, the researchers say, their experiment raises several issues about its applied potential.
"How similar are people's everyday mental activities (listening to music, telling a story, doing mental calculations, trying to remember something while driving, listening to a soccer match, etc.) while driving normally, to the artificial mental tasks proposed in our experiment? Which part of these tasks is verbal and which is a spatial-imagery component? How does the effect of the mandatory component of the mental tasks in the experimental context compare with the spontaneous nature of normal mental activity?
"Despite the lack of answers to these questions, this first research on the effects of mental activity on driving suggests the convenience of raising drivers' awareness about the possible consequences of driving while their attention is focused on their own thoughts, unrelated to driving."
Comments to this article have been disabled.
