Will That Sugar Rush Help You Get Stuff Done?


That afternoon candy bar may not be necessary if you’re trying to finish a tough task. Believing you have the willpower can do the trick, researchers say in a new study.

“The dominant theory about willpower is that it’s easily depleted and depends on a consistent supply of glucose from the outside,”

says Carol Dweck, professor of psychology at Stanford University and one of the study’s authors.

Through a series of experiments, researchers examined participants’ beliefs about willpower, defined as the ability to resist temptation and stay focused on a demanding task, and tested whether, and when, they experienced a lull in it.

They found that people who believe willpower is abundant didn’t need sugar to persevere through two difficult tasks. The people who believed willpower was limited, however, did do better on a difficult task after a sugary drink.

“When you have a limited theory of willpower, you’re constantly on alert, constantly monitoring yourself. ‘Am I tired? Am I hungry? Do I need a break? How am I feeling?’ ” Dweck says. “And at the first sign that something is flagging, you think, I need a rest or a boost.”

“We’re not saying people don’t need fuel for strenuous work, they just don’t need it constantly. People have many more resources at hand than they might think.”

Sugar Habit Society

The team believes there are important implications in society, where people struggle with diabetes and obesity, if people overuse sugar to tap into their willpower.

“It’s really important for them to know that in order to keep on working on a task—be it a diet or job assignment or school work—they don’t have to ply themselves with sugar as some earlier studies have suggested,” Dweck says.

The researchers found that people could be taught to think differently about willpower and that affected whether sugar helped their performance.

“We put them in different mindsets, either believing willpower is limited or believing it’s more self-generating,” Dweck says.

Dweck says they don’t yet know why certain people believe one theory over the other.

“We want to design interventions to teach people how to harness their considerable willpower,” she says.

Veronika Job, Gregory M. Walton, Katharina Bernecker, and Carol S. Dweck
Beliefs about willpower determine the impact of glucose on self-control
PNAS September 10, 2013 vol. 110 no. 37 14837-14842

Photo: Sun Brockie/Flickr