Dr. Bamberger, a co-author on that earlier study as well, said that many of the physicians weren’t even conscious that someone had been rude. “It was very mild incivility that people experience all the time in every workplace; things slip out that maybe shouldn’t slip out.” But in response to even mild rudeness, he said, people need to expend cognitive resources deciding whether they are in a threatening situation, and whether the threat is going to get worse; those concerns can draw cognitive resources away from the task at hand, and teamwork suffers.

The findings are consistent with earlier studies of rude behavior in other workplace environments, which have shown that even mild rudeness can have a potentially big impact. In both of the NICU studies, the effects on performance were significant; rudeness explained more error than the levels of error that have been shown to result from sleep deprivation.

Both studies were done in Israel, but the impact of rudeness does not seem to be culturally bound, a concern that was raised in the initial study design. “Israelis are not deemed to be the most polite people in the world; they say what’s on their mind,” Dr. Bamberger said. “The evidence suggests that even in a somewhat rude society, it still has an effect.”

In the latest study, the teams again knew that they were being observed while they dealt with simulated medical emergencies: a very premature birth, a baby in respiratory distress, a newborn severely deprived of oxygen. They were also told they would need to respond to family members while taking care of the critically ill babies, standard everyday imperatives in newborn intensive care.

The new study also looked at two different strategies to see whether they might help the teams deal with the rudeness.

In one, the medical personnel were asked to do a writing exercise immediately afterward, imagining the story from the mother’s point of view. But that narrative exercise seemed to have no effect on subsequent performance.

The other intervention did seem to provide some benefits. In that exercise, staff members were asked to play a computer game before the simulation, developed for people with post-traumatic stress disorder. In the game, participants were exposed to faces showing different emotions, rating them as either “angry” or “happy.” Then, after their threshold for perceiving threats — the angry faces — was established, they got feedback designed to raise that threshold, to help deflect their focus on minor threats.