The phrase "ego depletion" might not mean much to laymen, but to psychologists, it's a very big deal indeed, writes Daniel Engber at Slate. The general idea is that people have a finite amount of willpower at any one time, meaning they can use it up performing one task and then bomb on a second one that requires more of it. The premise was laid out in an influential study out of Case Western nearly 20 years ago involving chocolate chip cookies, and since then an entire psychological field has been built around it. The problem? "It now appears that ego depletion could be completely bogus, that its foundation might be made of rotted-out materials," writes Engber. In the original study, participants entered a room smelling of freshly baked chocolate chip cookies and found two bowls, one with cookies and one with radishes. Some were allowed to eat the cookies, but some had to settle for the radishes only.
Both groups were then given an impossible puzzle to solve, and the group that had to fend off their desire to eat the cookies ended up bailing on it much more quickly than the other group. Thus, "ego depletion" came into vogue. Since then, hundreds of similar studies seemed to back up the work. Next month, however, a paper in the journal Perspectives on Psychological Science will make the case that the pillars of ego depletion—that one task can drain our supplies of mental strength and that we can actually replenish our reserves through certain exercises—cannot be confirmed. It's no minor argument: The authors studied more than 2,000 subjects at two dozen labs around the world. The upshot is that "an entire field of study—and significant portions of certain scientists' careers—could be resting on a false premise," writes Engber. "If something this well-established could fall apart, then what's next? That's not just worrying. It's terrifying." Click for his full piece. (Read more psychology stories.)