People with higher levels of the hormones testosterone and cortisol are more likely to cheat and feel good about their unethical behaviour, a new study has found.
Hormones play a two-part role in encouraging and reinforcing cheating and other unethical behaviour, researchers said.
According to the study by researchers at the Harvard University and The University of Texas at Austin, the endocrine system plays a dual role in unethical acts.
First, elevated hormone levels predict likelihood of cheating. Then, a change of hormone levels during the act reinforces the behaviour.
"Although the science of hormones and behaviour dates back to the early 19th century, only recently has research revealed just how powerful and pervasive the influence of the endocrine system is on human behaviour," said corresponding author Robert Josephs, UT Austin professor of psychology.
Researchers asked 117 participants to complete a math test, grade it themselves and self-report the number of correctly completed problems. The more problems they got correct, the more money they would earn.
From salivary samples collected before and after the test, researchers found that individuals with elevated levels of testosterone and cortisol were more likely to overstate the number of correctly solved problems.
"Elevated testosterone decreases the fear of punishment while increasing sensitivity to reward. Elevated cortisol is linked to an uncomfortable state of chronic stress that can be extremely debilitating," Josephs said.
"Testosterone furnishes the courage to cheat, and elevated cortisol provides a reason to cheat," he said.
Additionally, participants who cheated showed lowered levels of cortisol and reported reductions in emotional distress after the test, as if cheating provided some sort of stress relief.
"The stress reduction is accompanied by a powerful stimulation of the reward centres in the brain, so these psychological changes have the unfortunate consequence of reinforcing the unethical behaviour," Josephs said.
Because neither hormone without the other predicted unethical behaviour, lowering levels of either hormone may prevent unethical episodes.
Prior research shows that tasks that reward groups rather than individuals can eliminate the influence of testosterone on performance; and, many stress relieving techniques such as yoga, meditation and exercise reduce levels of cortisol, Josephs said.
"The take-home message from our studies is that appeals based on ethics and morality - the carrot approach - and those based on threats of punishment - the stick approach - may not be effective in preventing cheating," he said.