Willpower

surprised to find a hefty negative correlation.
    “Apparently,” he joked, “the students could either get their homework done or change their socks every day, but not both.”
    He didn’t give it much further thought, but decades later other researchers wondered if there was something to the joke. Two Australian psychologists, Megan Oaten and Ken Cheng, considered the possibility that the students were suffering from the sort of ego depletion revealed in the radish experiment. These psychologists started by administering laboratory self-control tests to the students at different times during the semester. As hypothesized, the students performed relatively badly near the end of the term, apparently because their willpower had been depleted by the strain of studying for exams and turning in assignments. But the deterioration wasn’t limited to arcane laboratory tests. When asked about other aspects of their lives, it became clear that Bem’s dirty-sock finding hadn’t been a fluke. All sorts of good habits were forsaken as the students’ self-control waned during exam period.
    They stopped exercising. They smoked more cigarettes. They drank so much coffee and tea that their caffeine intake doubled. The extra caffeine might have been excused as a study aid, but if they were really studying more, you’d expect them to be drinking less alcohol, and that didn’t happen. Even though there were fewer parties during exam time, the students drank as much as ever. They abandoned healthy diets and increased their consumption of junk food by 50 percent. It wasn’t that they suddenly convinced themselves that potato chips were a brain food. They simply stopped worrying about unhealthy, fattening food when they were focused on exams. They also became less concerned about returning phone calls, washing dishes, or cleaning floors. Final-exam time brought declines in every aspect of personal hygiene that was studied. The students became less diligent about brushing and flossing their teeth. They skipped washing their hair and shaving. And, yes, they wore dirty socks and other unwashed clothes.
    Could all of this merely reflect a practical, if slightly unhealthy, shift in priorities? Were they sensibly saving time so that they could study more? Not quite. During exams, students reported an increase in the tendency to spend time with friends instead of studying—precisely the opposite of what would be sensible and practical. Some students even reported that their study habits got worse during exam time, which couldn’t have been their intention. They must have been devoting much of their willpower to making themselves study harder, and yet they ended up studying less. Likewise, they reported an increase in oversleeping, and in spending money impulsively. Shopping sprees made no practical sense during exam period, but the students had less discipline to restrain their spending. They were also more grumpy, irritable, and prone to anger or despair. They may have blamed their outbursts on the stress of exam period, because there’s a common misperception that stress causes those kinds of emotions. What stress really does, though, is deplete willpower, which diminishes your ability to control those emotions.
    The effects of ego depletion were recently demonstrated even more precisely in the beeper study in Germany that we mentioned earlier. By using beepers to query people about their desires throughout the day, Baumeister and his colleagues could see how much willpower was being exerted as the day went on. Sure enough, the more willpower people expended, the more likely they became to yield to the next temptation that came along. When faced with a new desire that produced some I-want-to-but-I-really-shouldn’t sort of inner conflict, they gave in more readily if they’d already fended off earlier temptations, particularly if the new temptation came soon after a previous one.
    When they eventually yielded to temptation, the German adults as well as the American college students probably blamed their lapses on some flaw in their character: I just don’t have enough willpower. But earlier in the day, or earlier in the semester, they’d all had enough willpower to resist similar temptations. What had happened to it? Was it really all gone? Perhaps, but there was also another way to interpret the research on ego depletion. Maybe people didn’t simply run out of willpower. Maybe they consciously or unconsciously hoarded it.