An important finding of the study was the extremely low levels of problem behaviors that occurred throughout the study for both participants. Given their long histories of both negative and positive reinforcement for problem behavior, it was possible that participants would engage in problem behavior rather than select the break option, because no preferred edibles were available during the break time. Neither of the participants, however, engaged in problem behaviors on trials in which the break option was selected even though preferred items were not available. Although Ian did show some problem behaviors during a small proportion of the sessions, the behaviors were less severe than those typically reported by his caregiver, and in each case when the choice between work and break was represented following an instance of problem behavior, Ian chose to complete the tasks, and no additional instances of problem behavior occurred.