When your lovelorn guy friends grumble that “nice guys finish last,” you swear it isn’t so. But they may be right… at least when it comes to income.Nice, agreeable men earn significantly less income than their disagreeable, stubborn, fight-to-the-death colleagues, says a new study in the Journal of Personality and Social Psychology. Disagreeable meaning someone willing to aggressively fight for a cause during conflict, that is (i.e., Jerry Maguire’s “show me the money” tenacity), not just your everyday curmudgeon.MORE: Are Beautiful People Rude?The study found that agreeable men—defined with take-home-to-mom traits like trust, altruism, compliance and straightforwardness—earn about $7,000 less than their disagreeable male colleagues in the workplace. Apparently, “plays well with others” pulls more rank in the sandbox than the boardroom.“At least in Western cultures, competitiveness and aggression are rewarded in the workplace while humility and accommodation are not,” says Cornell University professor Beth Livingston, one of the study’s lead researchers. “Our research further demonstrates how far this workplace norm can go, such that even for people in the same jobs with the same education and ability, being disagreeable pays.”In one part of the study, subjects were even given hypothetical job candidates, all described as smart and highly qualified, and were asked who should be fast-tracked to management. You guessed it: Candidates who were also described as altruistic, humble or trusting weren’t given the go ahead; others were.RESEARCH: Blondes Earn More MoneyBut what about women in the workplace? Do nice women finish last too?Not necessarily. The study showed that (unfortunately) women entering the work force earn about $4,787 less than their male colleagues, and that—shockingly—agreeableness was an irrelevant factor. Go ahead and shelve that copy of “Nice Girls Don’t Get the Corner Office,” and be as cooperative or controversial as you want, ladies. Female income didn’t budge, nice or not.It’s important to remember though, the qualities that behoove the corporate ladder usually aren’t the same traits we appreciate as loving, caring, giving human beings. So to all the nice (albeit pay-deprived) men and women out there: Keep it up! Money isn’t everything, and as always, kindness counts.MORE: More Money, More Marriage Problems