It’s hard to think of a situation in which it wouldn’t be extremely useful to have more willpower. For a start, your New Year’s resolutions would no longer be laughably short-lived. You could stop yourself spending all day on social media, spiralling into despair at the state of the world, yet also summon the self-discipline to do something about it by volunteering or donating to charity. And with more “political will”, which is really just willpower writ large, we could forestall the worst consequences of climate change, or stop quasi-fascist confidence tricksters from getting elected president. In short, if psychologists could figure out how to reliably build and sustain willpower, we’d be laughing.

Unfortunately, though, 2016 was the year in which psychologists had to admit they’d figured out no such thing, and that much of what they thought they knew about willpower was probably wrong. Changing your habits is certainly doable, but “more willpower” may not be the answer after all.

The received wisdom, for nearly two decades, was that willpower is like a muscle. That means you can strengthen it through regular use, but also that you can tire it out, so that expending willpower in one way (for example, by forcing yourself to work when you’d rather be checking Facebook) means there’ll be less left over for other purposes (such as resisting the lure of a third pint after work). In a landmark 1998 study, the social psychologist Roy Bauermeister and his colleagues baked a batch of chocolate cookies and served them alongside a bowl of radishes. They brought two groups of subjects into the lab, instructing each to eat only cookies or only radishes; their reasoning was that it would take self-discipline for the radish-eaters to resist the cookies. In the second stage of the experiment, participants were given puzzles to solve, not realising that they were actually unsolvable. The cookie-eaters plugged away at the puzzles for an average of 19 minutes each, while the radish-eaters gave up after eight, their willpower presumably already eroded by resisting the cookies.

Thus was born the theory of “ego depletion”, which holds that willpower is a limited resource. Pick your New Year resolutions sparingly, otherwise they’ll undermine each other. Your plan to meditate for 20 minutes each morning may actively obstruct your plan to learn Spanish, and vice versa, so you end up achieving neither.

Some scholars argue that willpower is better understood as being like an emotion: a feeling that comes and goes

Except willpower probably isn’t like a muscle after all: in recent years, attempts to reproduce the original results have failed, part of a wider credibility crisis in psychology. Meanwhile, a new consensus has begun to gain ground: that willpower isn’t a limited resource, but believing that it is makes you less likely to follow through on your plans.

Some scholars argue that willpower is better understood as being like an emotion: a feeling that comes and goes, rather unpredictably, and that you shouldn’t expect to be able to force, just as you can’t force yourself to feel happy. And, like happiness, its chronic absence may be a warning that you’re on the wrong track. If a relationship reliably made you miserable, you might conclude that it wasn’t the relationship for you. Likewise, if you repeatedly fail to summon the willpower for a certain behaviour, it may be time to accept the fact: perhaps getting better at cooking, or learning to enjoy yoga, just isn’t on the cards for you, and you’d be better advised to focus on changes that truly inspire you. “If you decide you’re going to fight cravings, fight thoughts, fight emotions, you put all your energy and attention into trying to change the inner experiences,” the willpower researcher Kelly McGonigal has argued. And people who do that “tend to become more stuck, and more overwhelmed.” Instead, ask what changes you’d genuinely enjoy having made a year from now, as opposed to those you feel you ought to make.

One tactic is to manipulate your environment in such a way that willpower becomes less important

Lurking behind all this, though, is a more unsettling question: does willpower even exist? McGonigal defines people with willpower as those who demonstrate “the ability to do what matters most, even when it’s difficult, or when some part of [them] doesn’t want to”. Willpower, then, is a word ascribed to people who manage to do what they said they were going to do: it’s a judgment about their behaviour. But it doesn’t follow that willpower is a thing in itself, a substance or resource you either possess or you don’t, like money or muscle strength. Rather than “How can I build my willpower?”, it may be better to ask: “How can I make it more likely that I’ll do what I plan to do?”

One tactic is to manipulate your environment in such a way that willpower becomes less important. If you don’t keep your credit card in your wallet or handbag, it’ll be difficult to use it for unwise impulse purchases; if money is automatically transferred from your current account to a savings account the day you’re paid, your goal of saving won’t rely exclusively on strength of character. Then there’s a technique known as “strategic pre-commitment”: tell a friend about your plan, and the risk of mild public shame may help keep you on track. (Better yet, give them a cheque made out to an organisation you hate, and make them promise to donate it if you fail.) Use whatever tricks happen to fit your personality: the comedian Jerry Seinfeld famously marked an X on a wallchart for every day he managed to write, and soon became unwilling to break the chain of Xs. And exploit the power of “if-then plans”, which are backed by numerous research studies: think through the day ahead, envisaging the specific scenarios in which you might find yourself, and the specific ways you intend to respond when you do. (For example, you might decide that as soon as you feel sleepy after 10pm, you’ll go directly to bed; or that you’ll always put on your running shoes the moment you get home from work.)

The most important boost to your habit-changing plans, though, may lie not in any individual strategy, but in letting go of the idea of “willpower” altogether. If the word doesn’t really refer to an identifiable thing, there’s no need to devote energy to fretting over your lack of it. Behaviour change becomes a far more straightforward matter of assembling a toolbox of tricks that, in combination, should steer you well. Best of all, you’ll no longer be engaged in a battle with your own psyche: you can stop trying to “find the willpower” to live a healthier/kinder/less stressful/more high-achieving life – and just focus on living it instead.