The Spanish Train Crash and a Driver’s Brain
On August 8th 1996, my editor-colleague Ruth Holland left her office at the British Medical Association in London and walked the short distance to Euston station, where she boarded the 17.04 train to Milton Keynes. 20 minutes later, she was dead, killed in a crash after the train driver passed through a red light and hit another train at Watford South Junction.
The enquiry into Ruth’s accident found that her driver “did not react correctly to two signals set at caution”, namely, he ran through two yellow lights before passing through the final red light.
Francisco Garzón, the driver of the train which crashed last Wednesday night killing 78 people, allegedly told the investigating judge that he had had a ‘lapse of concentration’ and did not slow down for the 80kph limit on the deadly curve which derailed his train.
We do not know for sure what caused Garzón to go more than twice as fast as he should have, but we do know that Ruth Holland died because her driver’s attention lapsed and this may have also played a part in the Spanish crash.
Over the last 25 years I have studied lapses of attention and it turns out that keeping your mind focused on a routine, repetitive, routine task like driving a train, bus, car or plane is one of the hardest things for the human brain to do.
So hard is it to do, in fact, that ever since Adolf Hitler started building the first ‘autobahns’ – motorways or freeways – civil engineers have discovered that they have had to build totally physically unnecessary bends into these highways – simply to keep drivers alert. Over the 80 year history of the fast, long-distance highway, trillions of dollars will have been spent for no other reason than to keep switched on a crucial network in driver’s brains.
This brain network allows us to concentrate on undemanding, routine activities – like easy, unchallenging driving. But you also need it for studying, reading, following a lecture or listening for your flight to be announced at the airport.
The system is called the sustained attention system, and is controlled by the right half of your brain – particularly outside surface of your right frontal lobe. It is also closely linked to a chemical messenger in the brain called noradrenaline. People with attention deficit hyperactivity disorder have real problems with this type of attention and many of them have chronically low levels of noradrenaline in their brains which makes them restless, sensation seeking, and attracted to alertness-boosting drugs like nicotine.
The critical feature of this attention system is that it is internally driven – ie you keep your mind on the road/book/lecture in spite of the fact that the road/book/lecture has no attention-grabbing features about it. Here, your attention is internally controlled.
Contrast this with situations where your attention is externally controlled – by a really stimulating computer game, by a very exciting or sexy movie or by the narrative tension of some brilliantly-scripted film. Here your attention is in the hands of the director – they have your brain like putty in their hands – and in particular your right hemisphere vigilant attention system. Here our internal control system can have a rest, because it is externally controlled. People with ADHD have much less difficulty attending in this sort of situation – which can be a puzzle for their relatives and even some doctors who can’t understand how they can concentrate for hours on ‘Medal of Honor’ but only for seconds on reading a textbook.
Civil engineers figured this out long before cognitive neuroscientists like me did and began to build bends into roads so that they could externally control the attention of drivers and stop them driving off the road.
The problem with being in controls of hundreds of tons of steel travelling at hundreds of miles per hour is that there is little external stimulation to keep your attention focussed – everything depends on that right front part of your brain to keep you checking that your mind is on the task in hand.
Unfortunately, the driver of Ruth Holland’s train wasn’t able to do this for a few crucial tens of seconds, and it may be that Francisco Garzón’s attention may have drifted in that crucial interval where he was supposed to slow down the train, though we will have to wait for the enquiry to know for sure.