Supervisors who are abusive to their individual employees infect the entire work team and hurt productivity, according to a recent study.

Researchers from Michigan State University suggest that the toxic effect of nonphysical abuse by a supervisor is much broader than believed. They found that supervisors who belittle and ridicule workers not only negatively affect those workers' attitudes and behaviors, but also cause team members to act in a similar hostile manner toward one another.

"That's the most disturbing finding," Crystal Farh, lead investigator of the study, said in a statement. "Because it's not just about individual victims now, it's about creating a context where everybody suffers, regardless of whether you were individually abused or not."

For the study, Farh and Zhijun Chen from the University of Western Australia studied 51 teams of employees from 10 firms in China. Average team size was about six workers and the teams performed a variety of functions including customer service, technical support and research and development.

They looked at nonphysical abuse such as verbal mistreatment and demeaning emails. Employees who directly experienced such abuse felt devalued and contributed less to the team. At the same time, the entire team "descended into conflicts," Farh added, which also reduced worker contributions.

"Teams characterized by relationship conflict are hostile toward other members, mistreat team, speak to them rudely and experience negative emotions toward them," Farh said.

The experiment was replicated in a controlled laboratory setting in the United States, with nearly 300 people participating.

Farh said the findings could likely be explained by social learning theory, in which people learn and then model behavior based on observing others, in this case the boss. Previous research has shown that workers emulate supervisors' positive behaviors, she explained, so it only makes sense they would follow negative behaviors as well.

Researchers said the findings have implications for companies faced with rehabilitating a team of employees following abusive supervision.

The findings were recently published in the Journal of Applied Psychology.