One Rule-Breaker Can Spoil the Bunch

New research suggests the "bad apple" metaphor isn't just a cliché—it can set off a chain reaction. In an online experiment with 750 Americans, University of Amsterdam researchers paid people to pick the brightest square on a grid, then secretly gave bigger payouts for cheating by picking squares farther to the right, the Guardian reports. After making an initial choice, participants were given information on another player's choice and political affiliation, and asked if they wanted to revise their pick, according to the study published in Proceedings of the Royal Society B.

While a sizable minority stuck to the rules, rule-breaking by others often nudged people into similar violations, with some pushed to break rules even more aggressively. The effect was strongest when the cheaters shared political affiliations, suggesting a high degree of group influence. Outside experts caution the lab setup lacks real-world penalties, so how far this extends to actual misconduct is unclear. Still, the effect could explain how a few deviant individuals turn peaceful protests violent or highways into speedways, study author Lucas Molleman tells Science News.