“Try? Try? There is no try. Only do.” –Master Yoda

Some people believe that will power is a bodily function that requires glucose to power it. An interesting idea, especially if you are using your will power to resist eating sugar. The belief must also technically be true, at least at its most fundamental level, since will power—if such a thing actually exists (I wouldn’t know)—must be a function of the brain. Since the brain needs glucose like any other organ, it must be that will power burns glucose. But so what? In this sense it’s trivial because everything burns glucose. The current believe on will power is more specific: it says that will power depletes glucose and that ingesting glucose hastens the recovery of will power. So, if you invoke will power does it also deplete all your other sugar-loving bodily functions? Like, um, life itself? Can you literally will yourself into an insulinemic coma, sucking all the sugar from your blood in a flurry of OCD-like focus on, well, anything?

Carol Dweck, of Stanford University, didn’t think so. She contributed her inaugural article as a new member of the National Academy of Science to their proceedings journal (PNAS), which tested the alternative theory that will power’s success, and depletion, depends more on the attitude of the wielder than on glucose consumption. If you believe that will power can be depleted, it will be, and vice versa.

The scientists asked hundreds of subjects whether they thought will power could be depleted and then asked them to drink either a sugary soda or a diet soda, followed by a pair of demanding tasks involving self-control The sugar drinkers did better, and lasted longer, if and only if they believed will power was depletable.