We’ve all done it. After a few days of successfully exercising self-restraint, the stresses of work, daily life and the New Year get the better of us. Our willpower cracks and the chocolate cupboard gets raided. Those plans to turn a daily trip to the gym into a habit get kicked into touch and we revert to sticking on a boxset and bidding farewell to the outside world.
Psychologists have coined a term for this all-too-common phenomenon: willpower depletion. It’s the idea that the more we put our willpower under strain, whether it’s through working hard or trying to stick to an exercise plan, the more it gets drained.
And the more it gets drained, the less self-control we have to resist other temptations, such as junk food, binge-watching a boxset or spending money on things we don’t need. Willpower depletion has been the conventional wisdom for decades.
But the more researchers are learning about it, the more they’re finding that rather than being a finite commodity that gets depleted as we use it, the extent of our willpower is actually something that we can control.
What happens to our willpower or self-control really matters. “Self-control is a huge predictor of success or failure in life,” says Prof Roy Baumeister at the University of Queensland in Australia. “People with better self-control are more popular, they do better at school and work, they are less likely to be arrested or divorced and they live longer.”
A test of wills
Baumeister is one of the main proponents of willpower depletion – an idea that can be traced back to Sigmund Freud in the 1920s. Over the past two decades, psychologists like Baumeister have dreamed up all kinds of creative ways to put volunteers’ willpowers to the test in their labs to see if they do get depleted.
In the first study of its kind in 1996, Baumeister and his team placed a pile of chocolate chip cookies and a bowl of radishes in front of psychology students. Some were allowed to tuck into the cookies; others were told they had to resist the temptation and only eat the radishes.
To crank up the strain on the radish eaters’ willpower, they ‘augmented’ the cookies (to use the researchers’ term) with a few chocolate sweets. The team even went to the trouble of baking the cookies in a little oven in the lab so it was filled with the aroma of freshly baked cookies.
All the students were then asked to trace a geometric shape using a pencil, without retracing any lines or lifting the pencil from the paper. Unbeknown to them, it was an impossible task. What they were being tested on, was how long they stuck at it – in other words, how much willpower they had left.
On average, the cookie eaters stuck with it for an impressive 18 minutes. Whereas the radish eaters, their willpower drained from resisting the temptation of the cookies, only lasted an average of eight minutes.
But more recently some psychologists have questioned whether our willpower does actually get depleted as we use it – or at least whether it gets depleted to the extent that the experiments that followed Baumeister’s 1996 study suggested.
In one huge study, conducted by psychologist Prof Martin Hagger, now at the University of California, Merced, 23 labs around the world carried out willpower depletion experiments in which volunteers completed tasks on a computer. The study found the willpower depletion effect to be small. In fact, in many instances it was so small that statistical analysis couldn’t rule out the possibility that there was no depletion at all.
The lab vs the real world
Baumeister stands by willpower depletion and the experiments that have been done. “There are something like 600 significant findings in the research literature,” he says. For his part, Hagger says willpower depletion is difficult to study in the lab – partly because it’s so tricky to put willpowers under strain there.
He says the best way to test for willpower depletion is to take the research out of the lab and into the real world. “What’s needed are field-based studies where you catch people in a depleted state – and that’s easier said than done.”
Nevertheless, there have been some field-based studies and these have provided some evidence that our willpower does get depleted when it’s put under strain. In one study carried out by Prof Mark Muraven, a psychologist at the University at Albany in the US, volunteers recorded how busy they had been at work and how stressed they had been in an electronic diary.
When they were busier and more stressed, their alcohol intake shot up. “When a situation places considerable demands on your self-control, it has the potential to impair your ability to inhibit your impulses,” says Hagger, who was not involved in the research.
But even if our willpower does have a tendency to get drained when it’s under strain, there are promising areas of research that show that we can still exert control over it – supercharge it, even.
One of these promising research areas is investigating the possibility of training our willpower by giving it a small workout. The idea is that, similar to the way physical training works on our muscles, if we regularly put our willpower under small amounts of strain, it may be depleted in the short term but it will get stronger in the long term.
There’s good evidence that this approach works. Prof Malte Friese at Saarland University in Germany worked with other psychologists to pool the results of 33 studies of willpower training involving 2,600 people to see if any trends emerged, in what’s known as a meta-analysis. Collectively, these studies showed that even small, regular tests of willpower can give your self-control a lift. It may only be a small lift, but it’s real.
The good news is that these willpower workouts don’t have to be especially taxing to have an effect. In one of the studies in the meta-analysis, Swiss students were asked to repeatedly perform an unrewarding menial task to train their willpower, squeezing a handgrip exerciser for as long as possible twice a day over two weeks. It seemed to be enough to boost their average marks in exams.
In another study, volunteers had to use their non-dominant hand for a set period of time. Exactly how these actions improve your willpower isn’t clear – one suggestion is that these willpower workouts work by increasing our perception of how much self-control we have.
A similar mechanism may well be at work in another area of research being conducted by a group of psychologists in the US and China – using rituals. Rituals are pre-defined sequences of actions we carry out that are repeated. And while some of the rituals being tested may seem bizarre, they seem to work wonders for our self-control.
In one experiment, women from a college gym in the US were asked to perform a ritual before they ate their food. They had to cut the food on their plate into pieces, rearrange them so the pieces were symmetrical then press their fork on the top of their food three times.
Those who performed the ritual ate 1,424 calories, on average, each day. Another group of volunteers from the gym who were encouraged to just think about the amount of food they ate each day during the research consumed 1,648 calories on average.
“The rigidity and the repetitiveness of the ritual behaviours really seem to be signalling to the person, ‘hey, I’m someone who has willpower,” says Dr Juliana Schroeder at the University of California, Berkeley, who was involved in the ritual research. “It’s a self-perception mechanism.”
Since repeated sets of actions that restrict food consumption can be associated with eating disorders, the researchers add that caution is needed but if undertaken carefully, they say that rituals can promote wellbeing.
The trouble with marshmallows and willpower
The most famous willpower experiment ever conducted is the ‘marshmallow test’. Developed in the 1960s by Stanford University psychologist Prof Walter Mischel (below), children aged three to five were left alone with a marshmallow and told they could eat it immediately but if they could resist eating the marshmallow for 15 minutes, they’d be rewarded with a second one.
When Mischel and his fellow researchers followed up with the same children in the 1990s, they found that those who had managed to hold out for the second marshmallow were doing much better, getting higher test scores and having lower BMIs.
But research published in 2018 tells a different story. Dr Tyler Watts at New York University along with Prof Greg Duncan and Haonan Quan at University of California, Irvine, staged a similar experiment. Only this time, the children were chosen to be representative of the general population in terms of their parents’ educations and other characteristics (the children in the original marshmallow test studies came from a Stanford University campus pre-school).
In the 2018 paper, they found that the children who were able to hold out for the larger marshmallow reward still did better, but to a much smaller degree than the original research showed. Not only that, but once factors such as their family background and parents’ educations were taken into account, the effect was even smaller.
Intriguingly, the researchers say that how long the children were able to delay eating the first marshmallow was strongly correlated to measures of their intelligence. So to a large degree, the marshmallow test may actually be testing how bright the children are rather than their level of self-control.
Will your way to willpower
Our perception of our willpower is a thread that runs through much of the recent research into how our self-control might be given a lift. But while most of the research has been carried out in Western countries, some has taken place elsewhere and it’s provided an intriguing insight into the inner workings of willpower.
In one study carried out by Dr Krishna Savani at Nanyang Technological University in Singapore and Prof Veronika Job at the University of Zurich, a group of undergraduate students in Bangalore, India, were given huge, difficult mazes to solve to stretch their willpower.
Others were given tiny, simple mazes. They were also tasked with pressing buttons when they saw the colours red, blue, green and yellow appear on their screens, and tested on how accurate they were. To make the test harder, the colours were spelled out but sometimes the word that appeared didn’t match the colour being displayed.
It was assumed that when willpower depletion took hold, the students given the huge, difficult mazes would perform worse in the colour task than those given the tiny, simple mazes. But that isn’t what happened. In fact, the exact opposite happened: those who had their willpowers put under strain by the huge mazes were actually more accurate in the second test.
The effect, referred to as reverse ego depletion, may be down to culture, says Savani. “Many Indian practices, such as meditation and concentration, emphasise the idea that people can exert willpower over extended periods and that it has a positive rather than a negative effect,” he says.
In other words, our beliefs about willpower influences our perception of what happens when we exercise it. If we believe that using our willpower is energising rather than draining, it is. Reverse ego depletion has been found in willpower studies in other non-Western countries too, such as China.
The good news is that our beliefs about willpower can be easily swayed. In one of Job and Savani’s experiments they gave a group of Indian and American volunteers what was said to be a scientific article stating that using willpower strengthens it. Another group received a different article saying using willpower diminishes it.
Those from both India and the US who read the article saying using willpower is strengthened performed better in a test after they had their willpowers put under strain. “This research shows that our beliefs about willpower are a self-fulfilling prophecy,” says Savani. “So people can be informed about this research and hopefully it will lead them to change their beliefs about willpower.”
If he’s right, it means that simply by reading this article you now have more willpower than you did before.