It has been suggested that self‐restraint, a phenomenon often correlated with self‐injurious behavior (SIB), may be maintained by negative reinforcement in the form of escape from the aversive properties of SIB (e.g., pain). We examined the effects of blocking SIB (and presumably removing any aversive effects) on the self‐restraint of a 19‐year‐old male with severe mental retardation. Consistent with the negative reinforcement hypothesis, blocking SIB resulted in near‐zero levels of SIB and moderate reductions in sel