Children will comprehensively copy others' actions despite manifest perceptual cues to their causal ineffectiveness. In experiment 1 we demonstrate that children will overimitate in this way even when the arbitrary actions copied are used as part of a process to achieve an outcome for someone else. We subsequently show in experiment 2 that children will omit arbitrary actions, but only if the actions are to achieve a clear, functional goal for a naïve adult. These findings highlight how readily children adopt what appear to be conventional behaviors, even when faced with a clear demonstration of their negligible functional value. We show how a child's strong, early-emerging propensity for overimitation reveals a sensitivity for ritualistic behavior.