28 | NewScientist | 2 August 2014

HAVE you ever wondered why you ended up at the office on a Sunday morning, when you were supposed to be heading to the supermarket? Why you find it so difficult to drive on the other side of the road when you are abroad? Or why you called your new partner by your old partner’s name? These slips let us know that habits have been taking care of a lot of our actions without us knowing.

Such trivial errors seem a small price to pay for the benefit habits bring – freeing up brainpower to devote to non-repetitive tasks. But what if they weren’t the only price? What if, without our knowledge, habits were shaping our beliefs and attitudes? My work is revealing the surprising power of habits.

The operating system of our brains has a limited capacity – much like an old PC that keeps freezing – and habits are a useful tool to get round this. If we can automate actions that we repeat often, we can save our cognitive resources for more taxing problems. Think of your first journey to a new workplace – all the route-planning, searching maps for the correct roads and looking out for landmarks to help you find your way. If every action we made throughout the day was this arduous, the simple task of tying our shoelaces would take as much effort as planning that first trip to the office. Luckily our brains are smarter than this, thanks to habits.

My research into habits began by looking at their role in obsessive-compulsive disorder (OCD), a condition where people feel compelled to perform irrational actions, such as endlessly washing their hands or dodging pavement cracks. These compulsive habits were, and still are, assumed by many to be driven by fear: obsessive worries about germs, superstitious thinking or even delusions.

Recent research has turned this notion on its head. Compulsive habits may be the driver of the irrational beliefs and worries, not the other way round.

The first evidence for this came from an experiment in which volunteers – some with OCD and some without – were trained to develop new habits in the lab. The task was simple: to avoid getting a shock to their wrist, participants could press on a pedal when they saw a yellow square on a computer screen. Later, their wrist was disconnected from the shocker, so there was no longer a need to press the pedal to avoid pain. Strikingly, those with OCD, but not those without, continued to

press on the pedal when they saw the square, even though, when asked, they said they knew it could no longer harm them. This told us that their pedal-pressing had become a habit (Biological Psychiatry, vol 75, p631).

But what was really fascinating about this study is that when we questioned the volunteers with OCD about their continuing habits again after the experiment, some invented explanations for their behaviour such as “I thought it could still shock me somehow”. These were the same people who had earlier reported that they knew they couldn’t be hurt. Why did they change their story? One possibility is that when someone performs an action that no longer makes sense, our brains jump in and tell a story that makes our behaviour seem more logical.

This finding called to mind a body of work dating back to the 1950s. We have known for a

long time that when behaviour contradicts belief it creates an uneasy feeling called cognitive dissonance, where two parts of our brain disagree. A classic example is smoking. The smoker knows it is harmful, but does it anyway. People try to minimise this internal conflict by altering their beliefs to match behaviour. Smokers who pride themselves on being rational in other aspects of their lives may justify their smoking habit using the excuse “I could get hit by a car tomorrow, I want to enjoy myself”.

In one of the earliest studies investigating this phenomenon, in 1959, psychologists Leon Festinger and James Carlsmith asked students to carry out a monotonous task for an hour, filling trays with spools of thread, emptying the trays then starting over again. Afterwards, some of the students were asked to tell the next participants arriving for the study that it had been an enjoyable task. The researchers found that students who gave these false reports changed their own feelings about the task, giving more positive ratings when asked how much they had liked it.

We now think this same backwards rationalising might be at play in people with OCD – much like how in our experiment those with the condition invented a fear to explain why they continued to press on the pedal. Perhaps feeling a compulsive urge to wash your hands is a very strange thing without a thought like “I’m worried about germs”.

Why can’t I stop?Everyone knows that thoughts cause actions which cause habits. What if this is the wrong way round, asks psychologist Claire Gillan

ProfileClaire Gillan is a Sir Henry Wellcome postdoctoral fellow at New York University and the University of Cambridge. She studies habit formation, especially in relation to obsessive-compulsive disorder

“ Is it possible that we have been thinking about OCD backwards for years?”

OPINION THE BIG IDEA

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2 August 2014 | NewScientist | 29

Is it possible that we have been thinking about OCD backwards for all these years? What if the obsessions are the consequence, rather than the cause, of the need to follow certain urges? What if the compulsive habits come first?

If this is how OCD works, then there is no reason to think that things are any different for the rest of us. We are all creatures of habit. Maybe a lot of our preferences are, in fact, just products of habit. Maybe we don’t take that favourite route to work because of the lighter traffic or the shady trees we can walk under, but simply because our brains have made a habit of this routine, and we come up with an interpretation later that make us sound more in control of our choices.

This phenomenon, where behaviour changes belief, is pervasive across all kinds of human behaviour. For example, when volunteers are forced to choose between two very similar holiday destinations, they form a much stronger liking for the one they choose, even though they were indifferent to begin with. Amazingly, the researchers who ran this study found that these preferences weren’t fleeting; they were still present three years later. This shows that the influence of our behaviour on our likes and dislikes isn’t just profound, but long-lasting.

It is now thought that this process of tweaking our beliefs to explain our behaviour is one way that habits can mutate from accidental slips to compulsive urges. By forming a new belief, our urges to perform habits are reinforced and strengthened until eventually we lose our ability to resist certain bad habits, even though we know they hurt us in the long run. In other words, OCD could be the result of a habit system that has run out of control.

Right now this is just a hypothesis but my colleagues and I are working on testing it in the laboratory at New York University. We are interested in mapping the brains of people who are more prone to forming habits and those who are less prone, and to gain a clear understanding of how habits are formed, how they influence our beliefs and, most importantly, how they can be broken .

It is important to recognise that compulsive habits aren’t unique to psychiatric disorders, but are part and parcel of all of our lives. Maybe we don’t really like chocolate all that much... maybe that’s just the way our brains justify our urge to overindulge. nGe

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Compulsive habits like avoiding pavement cracks can lift a lid on the mind’s inner workings

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