How great is your self-control, aka willpower? Can it withstand a daily commitment to clean eating and workouts at the gym after being assaulted by work stress all day? Conventional psychological wisdom argues the tendency to give in to the couch or cookies after a stressful day is testament to willpower depletion or diminished self-control. But contemporary research tends to challenge this theory. Willpower is not a limited resource that inevitably runs out, it argues, but a skill shaped by habits, rituals, beliefs, and context. With the right mindset, it can even be strengthened and sustained, BBC Science Focus reports. 

“Self-control is a huge predictor of success or failure in life,” says social psychologist Roy Baumeister. “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.” 

But that doesn’t mean people with self-control should always resist temptation (or tasty cookies), according to his research. In 1996, Baumeister led an experiment — the first of its kind — testing the willpower of psychology students. Small groups were presented with chocolate chip cookies and radishes. One group was welcome to eat the cookies while another group was told to refrain from eating the cookies. Then, he presented the students with a futile task and measured how long they attempted to complete it. Those who were told to resist the cookies gave up faster, with Baumeister and his team concluding it was due to the willpower they depleted by not eating the cookies. 

On the other hand, psychologist Martin Hagger posits that willpower can’t be accurately tested in a lab because creating the circumstances that would genuinely strain someone’s will is too “tricky.” He conducted a large study of willpower depletion experiments in 23 labs across the country and found the levels of depletion to be miniscule. Real life is a better place to test willpower, he says. 

“When a situation places considerable demands on your self-control, it has the potential to impair your ability to inhibit your impulses,” Hagger explains. “What’s needed are field-based studies where you catch people in a depleted state – and that’s easier said than done.”

Either way, the good news is willpower can grow and it’s influenced by mindset. Social psychologist Malte Friese conducted a meta-analysis of 33 studies testing whether willpower can be trained, like a muscle, and found that yes, consistent “willpower workouts” are effective. Something as simple as squeezing a handgrip twice a day or using one’s non-dominant hand for routine tasks boosted self-control and even exam performance. Precisely why willpower grew isn’t known, but it’s suspected to be due to the participants’ internal perceptions about their self-control. “Our beliefs about willpower are a self-fulfilling prophecy,” says researcher Krishna Savani. 

He co-led a study of volunteers from India and the United States in which students were given huge, difficult mazes to solve to stretch their willpower. But participants were primed before they began: One group read a scientific article that claimed using willpower strengthens it. The other group read an article that said using willpower depletes it. Participants from both countries who read the article that claimed willpower increased when challenged performed better in a test after having their willpower put under strain. “So people can be informed about this research and hopefully it will lead them to change their beliefs about willpower,” Savani says.