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So much of what we do in our day-to-day lives, whether it be driving, making coffee or touch-typing, happens without the need for conscious thought. Unlike many of the brain鈥檚 other unconscious talents, these are skills that have had to be learned before the brain can automate them. How it does this might provide a method for us to think our way out of bad habits.

Ann Graybiel of the Massachusetts Institute of Technology and her colleagues have shown that a region deep inside the brain called the striatum is key to habit forming. When you undertake an action, the prefrontal cortex, which is involved in planning complex tasks, communicates with the striatum, which sends the necessary signals to enact the movement. Over time, input from the prefrontal circuits fades, to be replaced by loops linking the striatum to the sensorimotor cortex. The loops, together with the memory circuits, allow us to carry out the behaviour without having to think about it. Or, to put it another way, practice makes perfect. No thinking required.

The upside of this two-part system is that once we no longer need to focus our attention on a frequent task, the spare processing power can be used for other things. It comes with a downside, however. Similar circuitry is involved in turning all kinds of behaviours into habits, including thought patterns, and once any kind of behaviour becomes habit, it becomes less flexible and harder to interrupt. 鈥淚f it鈥檚 a good habit, that鈥檚 absolutely fine,鈥� says neuroscientist Anil Seth at the University of Sussex, UK. 鈥淏ut if you ingrain a bad habit, that鈥檚 equally difficult to get rid of. You lose that moment of choice when you can decide not to do something.鈥�

Crucially, though, Graybiel鈥檚 team has shown that, even with the most ingrained habits, a small area of the prefrontal cortex is kept online, in case we need to take alternative action. If the brake pedal in our car stops working, for instance, our entire focus of attention shifts to the physical act of driving the car. This offers hope to anyone looking to break a bad habit, and to those suffering from habit-related problems such as obsessive compulsive disorder and Tourette鈥檚 syndrome 鈥� both of which are associated with abnormal activity in the striatum and its connections to other parts of the brain. These circuits could prove fruitful targets for future drug treatments. For now, though, the best way to get a handle on bad habits is to become aware of them (see 鈥�How to see the thoughts you don鈥檛 know you are having鈥�). Then, focus all your attention on them and hope that it鈥檚 enough to help the frontal regions resist the call of the autopilot. Or you could teach yourself a new habit that counters the bad one.

This article appeared in print under the headline 鈥�5. Run your life on autopilot鈥�