By Christian Jarrett

Those people with their gym-toned bodies and high-flying careers. Somehow they always seem to make different choices than the rest of us – fruit over chocolate, work over TV. It’s as if they are capable of super-human willpower, but a new study that’s currently in press at Social Psychological and Personality Science suggests it’s not so. Achieving your work and fitness goals is not about exercising self-control, the findings imply, rather it’s about avoiding temptation in the first place.

A lot of research on self-control has been conducted in the lab, rather than in people’s daily lives, and one of the most consistent findings is that the more of it you use in one situation, the less you have left over to resist other temptations. This idea that willpower is a limited resource has been challenged recently, but nonetheless it still seems intuitive that to achieve your long-term goals, you need sufficient willpower to resist the pull of short-term temptations – for example, to turn down the pleasure of a cookie today, for the longer-term aim of losing weight.

To test how these ideas play out in real life, Marina Milyavskaya at Carleton University and Michael Inzlicht at the University of Toronto used what’s known as an “experience sampling” method, combined with daily diaries, to follow the lives of 159 university students in detail for one week. When they signed up for the study, the students completed some personality and trait self-control measures, and listed four personal goals (examples included “learn French” and “improve my health”), then three weeks later they began the week-long period of intense record-keeping.

During this particular week, five times a day at random times, the students’ smartphone pinged and asked them to report whether they were currently experiencing a desire for any temptations, whether these temptations conflicted with any of their goals, whether they had exercised willpower to resist the temptation(s), and how depleted or mentally exhausted they were feeling in that moment. At the end of each day that week, they also completed a diary about how mentally exhausted or energised they had felt during that day. Finally, the researchers caught up with the students again at the end of the semester to find out how much progress they’d made on their four personal goals.

The surprising finding is that students who reported exercising more deliberate self-control through the main study week did not achieve more progress on their goals. Instead, it was the students who reported experiencing fewer temptations who achieved more goal success. This connection between temptations and achievement seemed to be explained by depletion or mental exhaustion. That is, students who experienced more temptations also tended to report feeling more mentally exhausted at night, whether or not they had tried to deliberately resist those temptations. In turn, experiencing more mental exhaustion was inversely correlated with goal success.

The researchers summed their results up, thusly: “Against popular and scientific wisdom, effortful self-control did not appear to play a role in goal-pursuit, suggesting that the immediate positive consequences of exerting willpower do not translate into long-term goal success.”

The lesson seems to be to accept that humans are weak-willed – the key to success therefore is to avoid temptation in the first place. Avoid the grocery store when you’re hungry. Don’t leave the cookie jar on the side in the kitchen. Make your bedroom an iPad-free zone. Don’t fight the devil on your shoulder, outwit him.

That might be one interpretation, but there are some caveats. The study was focused on in-the-moment acts of deliberate self-control, however the researchers did also measure the students’ trait self-control at the start. And students who reported being generally more self-disciplined tended to experience fewer temptations during the key study week. This suggests that self-control or willpower as a trait, rather than as an in-the-moment act, is relevant to goal success. Note however that the main results held even after controlling for trait self-control (i.e. even students with high trait self-control tended to show the same pattern of more temptation equalling less goal attainment, with acts of willpower being irrelevant).

Another thing – the main findings applied when comparing between participants, but not when looking at each individual’s level of success with their different goals. Focusing at the individual level, success at one particular goal over others was not connected to levels of goal-conflicting temptation experienced during the study week for that particular goal. It’s not clear why this is.

It also pays to consider that the study relied exclusively on the students’ reports of their own experiences and goal attainment, meaning there was a lot of subjectivity involved. It would be an advance for future similar research to incorporate some kinds objective measure of goal attainment and depletion.

Nonetheless, this study stands out from the crowd for taking questions about self-control and depletion into the real world. And the finding that acts of deliberate willpower were irrelevant to long-term success certainly gives pause for thought.

“Our results suggest that the path to better self-regulation lies not in increasing self-control, but in removing the temptations available in our environments,” the researchers concluded.