A lot more than workplace harmony is at stake when employees or bosses are rude, according to new research. Heated discussions, arguments, and snide comments cause people to lose concentration – and make mistakes, whether they are on the receiving end of the rudeness or just witnesses to it.

Writing in the British Medical Journal, Rhona Flin, a University of Aberdeen professor of applied psychology, reported that students who were insulted by a professor en route to a test performed worse on a series of memory tasks than students who hadn't received similar treatment.

"This reaction is probably caused by the emotional arousal caused by the rudeness, which resulted in a switchover of cognitive capacity to deal with the required emotional processing, or it may, more simply, be caused by distraction," Flin writes.

In another study, a student who was late for a group experiment apologized, but the person running the group responded: "What is it with you? You arrive late, you are irresponsible. Look at you, how do you expect to hold down a job in the real world?" The comment was made at normal volume, in a mild tone. But students who saw the exchange went on to perform worse on memory tests than a control group that hadn't seen it.

Flin cited a case last year of two Northwest Airlines pilots who were arguing as they flew from San Diego and proceeded to overshoot their destination – Minneapolis – by 150 miles because they were so distracted. The pilots later had their licenses revoked.

"The story illustrates the interplay between emotionally charged behaviour, namely arguing or rudeness, and cognitive skills, such as concentration," Flin wrote.

Surveys have shown that one in ten U.S. workers witness rudeness on a daily basis. And researchers Christine Porath and Christine Pearson, who've been studying incivility in the workplace for a decade, wrote in the Harvard Business Review that 48 percent of employees who are the targets of rudeness decrease their work effort, and 66 percent said their performance declined. The researchers surveyed several thousand employees and managers from a range of U.S. companies.