False-positive maintenance of self-injurious behavior by access to tangible reinforcers

Results of a functional analysis indicated that the hand mouthing of a woma n with developmental disabilities was maintained by multiple sources of con trol (sensory stimulation and access to a leisure item). Further assessment revealed that access to several other items also produced high rates of ha nd mouthing. However, direct observation conducted in the woman's home indi cated that none of these items was delivered contingent upon hand mouthing. When the consequence observed most frequently in the home was incorporated into the functional analysis, rates of hand mouthing were no higher than t hey were during an alone condition. We concluded that hand mouthing, althou gh maintained by automatic reinforcement, was also susceptible to social co ntingencies when exposed to them during assessment, thereby producing a par tially false-positive outcome.