In "Too Tired to Tell the Truth," published in the Journal of Experimental Social Psychology, a research team led by Nicole Mead and Roy Baumeister of Florida State University describe two experiments in which the exercise of self-control apparently lead to subsequent cheating. They conclude that “when self-control has been weakened by depletion of its resources, selfish and dishonest behavior may readily ensue.”
In the first experiment, participants (84 undergraduates) were asked to write a short essay. Half of them were instructed to not use words containing the letters A or N — a difficult task that required considerable self-control. The others were instructed not to use words using the letters X or Z, a restriction that required minimal effort to comply with.
Afterward, in what they were told was a separate experiment, the students were given a puzzle involving matching and adding numbers, and told they would earn 25 cents for each correct solution. Half of the participants had their work scored by a supervisor, while the others counted the number of correct answers themselves, and paid themselves accordingly out of an envelope of quarters.
Participants who performed the easy word test claimed 25 percent more correct answers in the self-scoring condition, which “suggests some dishonesty,” the researchers note. But those who performed the difficult word test claimed more than twice as many correct answers than their counterparts. This suggests “self-control research depletion led to dishonest behavior,” the researchers conclude.
For another look at self-control, this one through the eyes of dogs, click here.
A second, similar test found that participants who had been forced to exercise self-control were not only more likely to cheat, but also more prone “to put themselves in a situation that enabled cheating.” Those self-control-depleted people cheated three times as much as members of a control group.
In related research published last year, University of Minnesota psychologist Kathleen Vohs reported that the act of making decisions makes it more difficult to control one’s impulses. She noted at the time that "almost all of our previous research on this model has found that if you engage in self-control in one domain, you'll have less self-control in another domain.”
Together, these studies suggest that if you’ve been successfully engaging in self-control all day — say, by avoiding that plate of pastries in the workplace lunchroom — it’s best to avoid contact with any type of temptation that evening. You may find yourself unable to resist.