They’re too young to read Yelp reviews, but new research shows that preschoolers use gossip to help their peers avoid cheaters. Scientists asked a few dozen 3- and 5-year-olds to play a sharing game with two puppets. In each game, a child was supposed to give a puppet four tokens, or vice versa. One of the puppets always followed the rules, but the other cheated, giving the child too few or too many tokens. After the puppets left, the researchers brought a second child into the room and recorded any comments the first child made to the second one. Overall, only 23% of the 3-year-olds who spoke made a suggestion that had something to do with the puppet’s behavior (instead of things like its shirt color)—information that would be useful to the second child in deciding which puppet to play with, the team reports in the British Journal of Development Psychology. The 5-year-olds had better gossip. Fifty-four percent of them offered a reason for avoiding one puppet that related to that puppet’s unfair playing style, even if one puppet were breaking the rules by giving more tokens than agreed on. Because of a paucity of studies on this topic involving children, scientists previously had little evidence that people gossiped before approximately age 10. Gossip, other work has shown, helps adults form relationships with people who will cooperate with them and avoid bullies. And now we know that even preschoolers perform this valuable social function.