"Nice guys finish last" the old adage goes, and a new study suggests there just might be some truth to this dictum — at least when it comes to workplace earnings.
The study, published in the Journal of Personality and Social Behavior, found that men who described themselves as nice -- agreeable, cooperative and kind -- earned 18 percent less than men who characterized themselves as disagreeable and aggressive. Women earned the least amount of money, but women who called themselves disagreeable made about 5 percent more than their more friendly female counterparts.
Timothy A. Judge, a professor of management at the University of Notre Dame and lead author of the study, said the most significant finding showed that what works for men -- disagreeableness -- didn't work as well for women.
Two factors probably contribute to this, he said.
"First, I think people interpret disagreeable behavior by men and women differently," Judge wrote in an email to ABCNews.com. "Disagreeable men are [seen as] tough-minded and good negotiators. Disagreeable women are seen as "bit**es" or labeled in a similarly derogatory way. Think of Martha Stewart and Hillary Clinton. Appropriate behavior is somewhat gendered."
"It's age old — women who are assertive get perceived as being aggressive," said Joshua Klapow, clinical psychologist and associate professor at the University of Alabama at Birmingham School of Public Health. "It is a culturally bound factor that is not fair but highly prevalent."
Data from nearly 3,500 workers, ranging from recent college grads to those near retirement, were used in the investigation. The researchers collected the data from three American surveys -- the National Longitudinal Surveys of Youth, the National Survey of Midlife Development and the Wisconsin Longitudinal Survey -- which consisted of self-reported facts regarding work experience, salary and other personal information.
While findings like these often attract attention, Martin Binks, clinical director and CEO of Binks Behavioral Health PLLC, cautioned against taking these findings as fact.
Nice Guys Earn Less in the Workplace
"The study relies entirely on the individual's own perception of their agreeableness, which assumes high levels of self-awareness," said Binks. "In reality, often the most disagreeable folks we know in our workplaces are quite unaware that others perceive them this way."
Those who described themselves as disagreeable may pursue their own career interests and, in turn, salary negotiations, more aggressively, experts said.
"Of course, there is no doubt a certain correlation between disagreeableness and rudeness, but they're not the same," said Judge.
Judge believes the findings point to certain recommendations.
"I think people have to be assertive," said Judge. "Pay is not solely determined by your qualifications or economic factors. If leaders get the performance that they expect, we employees get the pay for which we ask."
But Klapow implored readers to take the findings with a grain of salt.
"Please don't read this study and try to immediately change how you act in the workplace," he said.
"My fear as a psychologist is people are looking for a competitive advantage in this economic environment, and they're setting themselves up to be fired," said Klapow. "Given the time we're living in right now, the release of this study has potential to drive people to act in an unproductive way."