The effects of physical restraint on self-injurious behaviour.

Two experiments investigated the effects of two durations (one and three minutes) of physical restraint on the rate of self-injurious behaviour of a profoundly retarded girl. In the first experiment, a reversal design was used in which three-minute and one-minute restraint conditions were used sequentially. In the second experiment, an alternating treatments design was used in which the two conditions were alternated within the same experimental phase. Physical restraint was made contingent on each instance of SIB during experimental sessions. In the first experiment, with the introduction of three-minute restraint phase SIB increased to a rate high than baseline. However, it was reduced to near-zero levels during the one-minute restraint phase when it followed the three-minute phase. Although three-minute restraint did reduce the rate of SIB in the second experiments, it was found that one-minute restraint was more effective. In both experiments one-minute restraint was found to be more effective than three-minute restraint in reducing the rate of SIB.