What do you think you're looking at?

11 May 2006

In a previous post, Auto IT alluded to the fact that drivers rarely have a good idea of where they are looking when driving. This may sound daft - it seems self evident that most people are very well aware of where their own eyes are pointing. Alas, this piece of common sense is actually nonsense. Studies that measure eye movements using non-intrusive computerised headgear, such as the system developed by Professor Mike Land at Sussex University, can demonstrate that where we think we look is rarely the same as where we actually look. Just as the eye sees mostly in monochrome but the brain fills in colour with an unconscious combination of memory and guesswork, so the brain fills in our impression of where we look with made up stuff.

Looking back through the literature turns up some interesting gems. In 2001, the prof strapped his gear to the helmet of Tomas Scheckter, then a Formula 3 racing driver, and measured what his eyes got up to during six wet laps of Mallory Park.

On ordinary roads, Land’s research shows that ordinary drivers tend to have consistent patterns of eye motion:

In general, drivers appear to look at the section of road about one second ahead of their current position. This remains fairly constant as speed of driving changes. This suggests a one-second buffer between the visual input to the system [ie the brain] and the motor action - turning the steering wheel appropriately. We also find that when approaching a bend in the road drivers look at or near the tangent point (or reversal point) of the bend – [the moving point on the kerb] where the inside edge of the bend [appears to] change direction. The consistency of this result between subjects suggests that looking at the tangent point when approaching a bend is important for successfully navigating the bend.

Racing drivers (or at least Scheckter) don’t tend to do this. They track the tangent point only on long sweeping corners; on other corners they look beyond the tangent point to assess whether they are on the correct racing line. Also, because braking accurately before a corner is much more important for a racing driver than when trundling home with the shopping, racers tend to flick their eyes from the apex to the outside kerbs as they approach a hairpin to accurately gauge approach speed.

They also tend to turn their head with a great deal of accuracy, to minimise the eye movements needed to track the visual cues that help them stay on the racing line.

Having once served as a test subject for one of Professor Land’s former colleagues, Auto IT can confirm that having your eyeball tracked is a disconcerting experience, particularly when the research assistant is an attractive member of the opposite sex. As mentioned earlier, a lot of eye movements are unconscious and, though we may deny it, eyes have a habit of wandering over curves other than those on the road ahead.

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