According to a new psychological study reported by the Medical Express Website, our ability to exhibit self-control to avoid lying, cheating, or stealing declines over the course of a day — making people more likely to be dishonest in the afternoon than in the morning.
 

"As ethics researchers, we had been running experiments examining various unethical behaviors, such as lying, stealing, and cheating," said researchers Maryam Kouchaki of Harvard University and Isaac Smith of the University of Utah's David Eccles School of Business, who published their findings in the journal Psychological Science.. "We noticed that experiments conducted in the morning seemed to systematically result in lower instances of unethical behavior."
 

In one experiment, they showed college students patterns of dots on a computer and asked them to identify whether more dots were on the left or right side of the screen. The participants were paid 10 times more money for selecting the right over the left — regardless of which side had more dots — creating an incentive to cheat and lie. The results showed that students tested between 8 a.m. and noon were less likely to cheat than those tested between noon and 6 p.m. — a phenomenon the researchers dubbed the "morning morality effect."
 

In a second experiment, participants were asked to fill in the blanks when presented with word fragments such as "_ _RAL" and "E_ _ _ C_ _." In the morning, participants were more likely to form the words "moral" and "ethical" than in the afternoon, when students tended to form the words "coral" and "effects."
 

The researchers believe one explanation for the findings is that self-control can be diminished by fatigue, a lack of rest, and making repeated decisions.