Force of habit

image: © iStock Photo | narvikk

It’s the part of your mind that makes you expert, but it can also kill you.

When Dr Key Dismukes was in Australia recently, he validated his theories about memory, habit and error by washing his car windscreen several times a day.

Dismukes, formerly chief scientist for human factors at NASA’s Ames Research Centre, was touring regional Victoria before speaking at the Australian Aviation Psychology Association’s symposium in Melbourne. Although habituated to driving on the right, he managed Australia’s left-side traffic with one exception.

‘About half the time, when I went for the turn indicators, I would switch on the windshield wipers instead,’ he said. (In North America, the indicator stalk is on the left of the steering column.) Dismukes arrived safely at the conference with a newfound appreciation of how habit can be ‘your best friend or worst enemy, if you work in a high consequence environment.’

‘We really have to have habits—unconscious expert execution of tasks—otherwise we are just novices at everything, forever,’ he says. ‘It works very nicely most of the time, but there are some situations where we can get into trouble.’

Habit capture is one such trap. ‘Basically we intend to follow a normal practice but deviate in one step. It’s that deviation that will get us into trouble because when we’re not consciously monitoring what we do, habit takes over and takes us back down the old path instead of the new one we intend.’

A 2002 study he co-wrote with Jon Holbrook and Jessica Lang Nowiski found habit capture was behind 19 per cent of flight deck errors.

‘In these situations pilots intend to substitute an atypical action for a habitual action normally performed in the situation, but forget and revert to habit,’ the study said. ‘Although the atypical intention is presumably “fresh” in memory, it must compete with the habitual intention for retrieval. The overlearning that protects habitual actions against forgetting during routine operations makes pilots vulnerable to error particularly when they are busy, fatigued, or interrupted. Cues for habitual tasks are so effective that they often initiate behavior automatically unless deliberate effort is made to inhibit the habitual response.’

But replacing habit with conscious effort is no solution. It literally goes against human nature, and often reduces performance.

‘When we’re trying to consciously execute a task we’re pretty clumsy at it,’ Dismukes says.

‘For example, an expert athlete trying to improve his or her performance will sometimes think about it too much, and the thinking interferes with the automatic smooth execution. For a pilot an example would be if you were trying to get your landings just right; sometimes you make them worse. So habit is generally your friend, but you need to keep an eye on it.’

Experience and research indicates that habit capture is particularly insidious in situations that are almost normal—but not quite.

Dismukes, who in addition to his academic qualifications in neuroscience is qualified as an air transport pilot and glider instructor, gives an example.

‘Let’s say I’m making a standard instrument departure from an airport that I’ve flown from many times before. The controller always gives me the same departure, something like: “fly runway heading, climb to 1200 feet, turn right to intercept the 060 radial”.

‘Today the clearance starts out the same, and says “fly runway heading, climb to 1200 feet, turn left”.

‘If I’m flying by myself, flying manually, workload is pretty high, I’m going to be busy, especially in instrument conditions. There’s a strong likelihood that as I reach 1200 feet, I’ll automatically turn right instead of left. My limited conscious awareness will be focusing very hard on flying the aeroplane and habit is going to take me where it usually does.’

The danger is when a novel demand is inserted in the middle of a habitual sequence. ‘If it were a completely different clearance you wouldn’t have the same problem because you can’t do it automatically.’

The key to understanding habit is to realise that it is unconscious, and not related to conscientiousness or diligence, which are conscious states. Dismukes did not empty the washer bottle of his rented car because he was some sort of absent-minded professor, but because his brain, like all human brains, operated largely on the unconscious level.

So what is consciousness for? ‘The people who think about these things are coming to the view that consciousness does several things, Dismukes says. “It’s an interpreter of what the unconscious mind is doing; it creates story to make sense of it; it detects conflicts. That’s particularly so when we’re aware that something has to be done differently,

‘Consciousness is important as evaluation—“Did I do that well? Could I do it better?”—but not for direct control.’

But consciousness can be trained to anticipate habit capture, Dismukes says. ‘I think about the pilots I know and respect, and the best pilot for commercial air transport is one who’s on the lookout, who anticipates problems, including problems in their own performance, who’s thinking, “How could I get in trouble here?” Who’s always reading accident reports, who thinks, “How could I have gotten into that? How would I avoid getting into that?” Our consciousness is for anticipating situations and coming up with plans for dealing with them, that is the skill, a higher order cognitive skill.

However, attempting to avoid habit capture runs the risk of another mental trap. Prospective memory, the act of remembering to remember something in the future, is one of Dismukes’s research specialisations. He says it is inherently difficult.

‘As far as we know there’s no skill for prospective remembering. Our brain’s not wired very well to remember things in the future. It has no alarm clock to remind us to do most things. We remember to eat because we have a kind of alarm clock—being hungry. We remember to go to sleep because there’s an alarm system—getting sleepy. But there is no alarm system that tells us now’s the time to make that telephone call, or set the flaps for take-off.

‘It’s not a skill-based thing, although being aware that we’re vulnerable, and thinking about defences such as procedures and cues, can help us defend ourselves.’

Because habit consists of unconscious responses to routine cues (approaching a corner cues using the turn indicators, for example), the best way to disrupt habit capture and stimulate prospective memory is to adopt non-routine cues.

The styrofoam cup over the power levers to remind pilots to select flaps before take-off, when they cannot be selected straight away because of runway slush, is a classic example, Dismukes says.

If a cue cannot be placed before an activity, then a warning immediately after it has been done wrongly is the next best thing. ‘Every time I hit the wrong stalk the windshield wipers would pop up, like they were telling me “you’ve got it wrong”,’ Dismukes says. In aviation, this is one of the roles of the pilot monitoring.

Another anticipatory technique is to reduce conscious workload as much as possible in those normal-but-different situations likely to create habit capture. Again this should be the job of the second pilot—the pilot monitoring.


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