The study, led by business school professors Aleksander Ellis of the University of Arizona and Michael Christian of the University of North Carolina, builds on previous research that found when people get tired, their self-control goes down. Without the mental resources necessary to regulate their behavior, people may have a greater tendency to break the rules at work.
This latest study examined the effects of sleep deprivation and caffeine intake on 229 college students, some of whom were paid to stay up all night. A group of those sleep-deprived students were given caffeine-laced gum that would provide about the same boost as a cup of coffee, while others chewed regular gum. Participants were given the option to lie to another person in order to earn more money in a basic lab task, at the expense of the other person's payout. Some were encouraged, by the experimenter who was administering the study, to lie.
The students who hadn't slept the night before the experiment were more likely to lie, at the urgings of the experimenter, than those who got a full night's rest. However, this effect was moderated in the caffeine group—students in this group were less likely to obey the experimenter and lie.
While the real-life application of these findings is debatable—even if the students were blind to the purpose of the study, they surely knew the risks of lying for an extra few bucks in a university study would be lower than, say, fudging the numbers on a company account—it does provide further, um, rather obvious, evidence that we're not at our best when we're sleepy. So yes, it's probably best to provide your workers with ample coffee supplies. Even better? Make sure they go home and get a good night's sleep.