He said the findings were “suggestive of a slippery slope.” But he added that it was still not entirely clear what was driving people down that slope.

For example, Dr. Shenhav said, it could be that the act of lying by itself increased the propensity for acting dishonestly, “like gradually pushing our foot off a brake.” Or that the subjects, who were not punished in any way for their dishonesty, concluded that lying in that environment was not so bad.

“We need to be cautious when generalizing to real-world dishonesty that is typically associated with threats of reprimand” or damage to someone’s reputation, he said.

In the study, the subjects — 80 adults, most of them university students — were asked to help the unseen partner guess the number of pennies in the jar. The partner, the subject was told, would then tell the researchers the guess. (The partner was in reality a confederate of the scientists.)

In some cases, the subjects were given an incentive to lie: They were told that they would be paid more if their partners overestimated the money in the jar, and that the higher the overestimation, the more they would be paid. Their partners’ payments, however, would depend on how accurate the estimates were.

In other cases, the participants were told that both they and their partners would be paid more for overestimating the number of pennies; still others were told that their payments depended on the accuracy of the estimates, while their partners would be paid more for overestimating.

Dr. Garrett said he hoped that the study could be repeated in other, more realistic settings, and that another study could be done to look at what might stop people from escalating their dishonesty.