As anyone who has ever tried a diet knows, exerting willpower can be exhausting. After a whole day spent carefully avoiding the snack machine and attempting to take mindful joy in plain baked chicken and celery sticks, the siren call of cookies after dinner may be just too much to bear. This idea—that exercising self-control gets harder the more you have to do it—is called ego depletion, and it’s one of the most well-known concepts in social psychology. There are popular books on it. Most of us have probably have personal experience with it.
But what if a huge study of thousands of people found no evidence for ego depletion? What if some cultures actually show reverse ego depletion—where exerting willpower actually makes exerting more willpower easier? What if I told you that ego depletion does exist—but only if you believe it does?
Do these recent studies mean that one of the most well-established phenomena in social psychology is headed for the dusty shelf of discredited theories? Does it mean that everything you thought you knew about willpower was wrong?