An urban myth popular in US universities concerns a group of psychology students who decide to play a trick on their lecturer. They conspire among themselves to nod, smile and express passionate interest whenever he's standing at one side of the podium, or whenever he raises his arms to gesture; the rest of the time, they look distracted and bored. By the end of term, he's spending every lecture teetering precariously at the podium's edge, his arms floating foolishly far above his head. He has fallen victim to good, old-fashioned "operant conditioning" – the rewards-based system of behaviour change pioneered in rats by BF Skinner.
If these mythical students had been truly ingenious, though, they wouldn't have shown such interest every time the lecturer moved to one side, or raised his arms, but only sometimes – because one of the most dependable findings of operant conditioning is that random rewards are more motivating than predictable ones. As the animal trainer Karen Pryor notes in Don't Shoot The Dog!, a dolphin rewarded with a fishy treat every six jumps will soon become lackadaisical about the five in-between ones; reward it at random, however, and it'll jump vigorously, never knowing which jump will bring fish. This is why slot machines are so addictive, and why we click compulsively on email and Twitter – not because we know we'll be rewarded with interesting messages, but because we might be. If slot machines delivered £1 every time you inserted 50p, you might use them, but you'd never get addicted.
Rightly or wrongly, the unique power of "intermittent variable rewards" makes them perfect for manipulating others: what is dog training, after all, except manipulating dogs? (Even dogless parents and spouses might find Pryor's book worth reading, given how transferable her techniques seem to be.) It's also surely why certain drama-loving people, prone to unpredictably conferring or withholding affection, seem to "addict" their partners, whether or not the manipulation's conscious. But it raises a sunnier prospect, too: might you be able to use random rewards to addict yourself to more positive behaviours?
Which brings me to Habit Judo, a crafty self-improvement scheme devised by a Michigan law student named Allen Reece, who was finding it hard to get new habits to stick. "That's the problem Habit Judo solves," he told me. "It provides enough additional incentive to get you over the motivation gap until the new habit becomes ingrained." His system involves rewarding yourself with a computer-generated random score between one and 10 every time you perform a desired behaviour. Your score gradually accumulates, and at certain thresholds you "qualify" for a real reward, such as a favourite food or "move up a level": Reece marks the levels by wearing wristbands in the colours of judo belts, hence the name. (In technology circles, the term for such ideas is "gamification", because videogames often deploy similar reward mechanisms – but then, so did Skinner, years before videogames.)
After years intending to meditate and get better at weightlifting, Reece now does those things. "It's so powerful and addictive that if I set flying as a new habit, in a couple of months I'd be a superhero," he says. AddictedMan: it has a certain ring.
oliver.burkeman@theguardian.com
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