Contrary to popular belief, there isn’t a magic number of repetitions that result in a habit forming. Some say that you need to repeat an action fifty times or for twenty-one days, but very few researchers have actually looked at this question systematically. And those that have done tend to find that there isn’t a clear-cut answer to the question. In one of the few studies to have tracked the formation of healthy habits in real-world settings, researchers studied ninety-six students who had just moved to university and were encouraged to repeat behaviours in response to consistent cues (such as ‘going for a walk after breakfast’). They found that habits formed in some of the students after eighteen days, but for some it took much longer – up to 254 days. The average was sixty-six days.
In a recent experiment, men were asked to rank how attractive they found photographs of different women’s faces. The photos were eight by ten inches, and showed women facing the camera or turned in three-quarter profile. Unbeknownst to the men, in half the photos the eyes of the women were dilated, and in the other half they were not. The men were consistently more attracted to the women with dilated eyes. Remarkably, the men had no insight into their decision making.
To test this theory, a few years ago I ran a study in which two groups of people were asked to take part in an experiment in which they spent an afternoon picking up litter in a London park. Participants were told that they were taking part in an experiment examining how best to persuade people to look after their local parks. One group were paid handsomely for their time, while the others were only given a small amount of cash. After an hour or so of backbreaking and tedious work, everyone rated the degree to which they had enjoyed the afternoon. You might think that those clutching a large amount of well-earned cash would be more positive than those who had given their time for very little money.
In fact, the result was exactly the opposite. The average enjoyment rating of the handsomely paid group was a measly 2 out of 10, while the modestly paid group’s average ratings were a whopping 8.5. It seemed that those who had been paid well had thought, ‘Well, let me see, people usually pay me to do things I don’t enjoy. I was paid a large amount, so I must dislike tidying the park.’