Self-control, it turns out, is a limited resource, “akin to strength or energy,” write the authors of the recent study. “As a result, any use of executive function appears to reduce the available quantity of this resource, resulting in poorer self-regulation in subsequent, even unrelated, tasks.” Yale’s Nathan Novemsky and Ravi Dhar, with Roy F. Baumeister of Florida State University and Jing Wang of Singapore Management University, ran an experiment in which subjects were presented with a series of choices. What the researchers found is that people are more likely to choose a “vice” when they have previously exercised self-control and chosen a “virtue.” Over the course of testing, this slow depletion of self-control passed without the subjects’ notice.
The researchers designed their experiment to push this insight one step further, investigating what kinds of choices are more likely to lead to subsequent poor impulse-control. They found that relatively inconsequential choices required little executive function, and thus didn’t deplete self-control. When the choice centered on an important trade-off, however, subjects evidenced a loss of willpower. In one pair of experiments, subjects were asked to make a variety of choices, including a choice between USB thumb-drives or an apartment choice trading off a short commute and affordable rent. These choices varied in how similar the options were. In other words, some had big trade-offs and others had small trade-offs. They were then asked to choose whether to watch a highbrow or a lowbrow movie, used to represent choices of virtue and vice, respectively. Those who had to settle the larger trade-off were also more likely to opt for the lowbrow movie. Thus the magnitude of trade-offs inherent in the choices we make, beyond the mere act of choosing, contributes to the breakdown of self-control.
The implications of these findings for individuals are spelled out clearly in the paper’s conclusion: “The best advice may be for individuals to conserve their resources for important choices and strategically yield to temptation when the consequences are less meaningful.” But while simple in principle, effectively putting the advice into practice may prove tough—just ask somebody midway through 2014, pausing to reflect on the state of his New Year’s resolutions.