The response set effect has been observed in a number of developmental tasks that are proposed to required inhibition. This effect has been interpreted as evidence that the specific responses children plan to make in these tasks become prepotent. Here we investigated whether there is a response set effect in the hand game. In this task, children need to suppress imitation and make a fist in response to a finger and point a finger in response to a fist. Following pilot data, we tested 7- and 11-year-olds (N = 36, Experiment 1) and then 5- and 6-year-olds (N = 40, Experiment 2). A response set effect was observed in the hand game with children 6 years of age and older. Thus, we obtained evidence consistent with a domain-general intentional mechanism that modulates prepotency. In the General discussion, we consider how this mechanism may work and how our findings relate to current theories of imitation.