Ever had a joke fall flat? It may be the sound of your voice, according to a new study. Researchers recorded men and women telling corny one-liners (ex., “I was thinking about life the other day, and a frightening idea occurred to me: What if the Hokey Pokey really is what it's all about?”)—and then manipulated the pitches of their voices. Artificially lowered voices made the speakers sound more dominant; higher pitched voices made them sound less so. Volunteer listeners then rated each joke’s funniness. Female listeners laughed or groaned regardless of the comic’s voice pitch, but for men it depended on how burly and dominant they were. Guys with bigger biceps and higher self-rated attractiveness were more likely to prefer lower-pitched jokes than less dominant listeners, and vice versa, according to a study in press in Evolution and Human Behavior. The researchers suggest humor may have evolved partly to help men form alliances for cooperative tasks like hunting. Dominant men make valuable allies—but only if you’re dominant enough not to be overpowered.