As long as you believe it, willpower can be plentiful. It is not a finite source, as new studies suggests. On top of that, nudging people's beliefs about willpower in one direction or the other can influence how they react or behave.

According to the findings, published in the journal Proceedings of the National Academy of Sciences, it contradicts earlier studies that suggested there is only so much of willpower we have. It's all in the mind it seems.

Willpower muscle

A number of researches suggest that willpower is like a muscle and that it could tire out if used too much. Other studies hinted that a physical boost could replenish willpower. In a study, participants were asked to drink a sugary drink and observed if they could maintain self control after a mentally challenging task.

The idea was to see if willpower depletes the brain's glucose supple. The result: a sugar rush would replenish people's willpower by refueling the brain, according to earlier research.

But what about those who push the limits in marathons and Ironman competitions going through hours without needing food the entire time? Simply taking a sip of a sugary drink without actually consuming it can have the same energizing effect.

"We have ample glucose supply in our bodies," said study co-author Carol Dweck, a psychologist at Stanford University.

In another study, subjects were asked to describe their beliefs about willpower. Some subscribed to the willpower as a muscle idea, whereas some just believed that it was plentiful and grows the more it is used.

Those who believed willpower was limited tired after the first task and performed poorly on the second. If they received a sugary drink that took effect after the first task, however, their second performance improved.

Those who believed willpower was abundant didn't tire during the second task, and got no boost from the sugar.

Power of belief


To rule out that willpower is influenced by what the mind believes, the team gave a second group of people a survey which was meant to make them believe willpower was finite or abundant.

Those who thought so tended to need a sugary drink to perform well, whereas those who believed they still had willpower didn't need the sugary drink.

The results suggest that physiologically, willpower shouldn't be depleted; rather, people's beliefs may be shaping their behavior, Dweck said.

Questions like "Am I tired", "Am I hungry" all kind of get in the way of willpower doing its thing. How you think and believe can greatly influence just how much of willpower you can muster out of yourself.

What do you think? Is it just a matter of blindly believing? Or does this have an actual effect on people? Care to try it out?