It’s late on a Friday afternoon. You’ve already spent hours on a mind-twisting task. But before you can turn in for the evening you have another demanding project that requires your attention. It’s going to take some serious willpower to stay focused. Will you power through? Or will you stagger to the weekend? The answer depends on how you think about your state of mind in this kind of situation.

Perhaps you think of willpower like fuel in a car – your reserves are already running low and the last project is going to drain you further. Or maybe you see willpower as sustained by a challenge – you’re feeling fatigued but you know engaging with the last project will recharge you.Ongoing research by psychologists suggests that these two perspectives on willpower are self-fulfilling. Just thinking that willpower is a limited resource makes it more likely that you’ll feel depleted after a demanding task. However, if you see challenges as motivation, you are more likely to perform as if your willpower is unlimited. Veronika Job at the University of Zurich and her colleagues at Stanford University tested this by asking 60 students whether willpower is a limited resource that’s depleted by effort, or if it’s potentially unlimited and recharged by a challenge. Next, the students were given two taxing mental tasks in succession. The first was an awkward editing task, the second involved naming the actual color of color words while ignoring their meaning (e.g. the word “green” written in red).

If you see challenges as motivation, you are more likely to perform as if your willpower is unlimited.