Between 2008 and 2015, groups of engineers at Volkswagen repeatedly faked car-engine emissions levels during laboratory tests. Engineers manipulated the vehicles to release pollutants at low levels in the lab so they could meet emissions standards in the U.S. and Europe. But when the cars hit the road, their emissions rates were much higher than allowable standards—up to 40 times higher in the U.S. The scam, dubbed “Dieselgate” in the press, had severe consequences. The additional pollution in the U.S. alone could contribute to dozens of premature deaths.

Dieselgate is just one example of what researchers call “collaborative dishonesty.” Often discussion of collaboration emphasizes its many advantages; group work improves social bonds and helps people solve complex problems they could not address alone. But there are other situations in which group work can become fertile ground for dishonest behavior, as it did in the Volkswagen scandal.

My colleagues and I pooled together data from many past studies to understand the forces that shape and underlie group dishonesty. Our work uncovered that unethical behavior is common in collaboration, but there are limits to the amount of lying that occurs—a finding that may help teams avoid falling into problematic behavior in the future.

We analyzed 34 relevant research articles by psychologists, economists and management researchers that involved more than 10,000 participants altogether. In these experiments, scientists asked people to play economic games or carry out decision-making tasks while part of a team. The specific instructions varied from one study to the next, but across experiments, participants could gain money through honesty and teamwork. In addition, they had opportunities to earn some additional money as a group by lying. For example, in some tasks, teams might receive a payout based on the number of puzzles they solved together; participants could lie and inflate the quantity they had deciphered for a greater monetary reward.

Across all studies and tasks, we found that groups tended to lie. On average, they earned 35.6 percent of the extra profits available to them above what they could make from simply telling the truth. The good news is that there was a limit to this deceit, which suggests people care about moral considerations to some extent. After all, groups did not, on average, earn 100 percent of the extra profits they could have made from their lies. In puzzle tasks, for instance, most teams did not simply pretend to solve every puzzle presented.

Additionally, when studies added ethical costs for dishonesty, such as informing people that lies would harm other participants or have negative consequences for a charity donation, groups lied less. On top of that, we discovered that when it comes to collaborative dishonesty, the gender and age of the group members mattered. The more women that a group had, and the older the group members were, the less the group lied. Past research suggests that women are penalized more than men for assertive and profit-maximizing behavior in general—for example, when they ask for a higher salary in a job interview. It is possible that this difference is one driver behind women’s higher levels of honesty both when working alone and in teams. This idea is speculative, however, and we’d need further investigation to know for sure.

We also ran an additional analysis that allowed us to study how collaborative dishonesty may escalate and spread over time. More specifically, several studies we analyzed involved asking pairs to roll dice over multiple rounds. One person rolled a die in private and then reported the outcome. Their partner learned about that report and then rolled an independent die before reporting that outcome as well. If both teammates claimed to roll the same number, they received a payout: for example, a 1-1 double might mean each person got $1, a 2-2 double could mean $2 each, and so on. Pairs could choose to be honest and receive payment only when they truly rolled doubles. But over the course of many rounds, some pairs would be tempted to falsely declare a higher or matching roll for greater or more frequent payouts.

For these studies, we first identified whether any participants were obviously deceitful. When the data suggested that certain individuals reported only 6’s—the highest roll possible—or only doubles in all rounds of the task, we identified these improbably lucky rollers as “brazen liars.” (Given that the chance of honestly reporting 6’s or doubles in 20 rounds, the most common number of rounds in the task, is very small—less than 0.001 percent—we felt confident about this classification.)

Then we examined the chances that a brazen liar’s behavior might influence their partner. The data were clear: dishonesty is contagious. Participants were more likely to be brazen liars when their partners were, too. Collaborative dishonesty also escalated over time. In later rounds, compared with earlier ones, the first person to roll a die was more likely to report higher die rolls, and their partner was more likely to report a double.

Collaborative dishonesty is clearly a hazard of group work. But our findings point to specific ways people could encourage honesty when groups work together. For instance, our discovery that collaborative dishonesty is contagious and escalates over time suggests that people should detect and act on early signs of dishonesty in groups. Several strategies could help. Managers can implement zero-tolerance policies toward even small acts of deceit to deter its escalation and spread. To increase early detection of dishonesty, they can put policies in place that forgive whistleblowers for their part in wrongdoing when they come forward about dishonest deeds. Finally, just as some managers ask their employees to report mistakes as soon as they occur to avoid larger downstream effects, a similar approach can be adopted when it comes to untruthful behavior. Catching collaborative dishonesty before it spreads could better nip it in the bud.

Knowing that groups are more honest when others are harmed by their lies suggests that we should highlight the negative consequences of collaborative dishonesty more prominently. In the case of Dieselgate, perhaps reminders of how excess pollution wreaks damage on society could have curbed the Volkswagen engineers’ willingness to manipulate vehicle engines in the first place.

Are you a scientist who specializes in neuroscience, cognitive science or psychology? And have you read a recent peer-reviewed paper that you would like to write about for Mind Matters? Please send suggestions to Scientific American’s Mind Matters editor Daisy Yuhas at pitchmindmatters@gmail.com.