Response acquisition under direct and indirect contingencies of reinforcement

We compared the effects of direct and indirect reinforcement contingencies on the performance of 6 individuals with profound developmental disabilitie s. Under both contingencies, completion of identical tasks (opening one of several types of containers) produced access to identical reinforcers. Unde r the direct contingency, the reinforcer was placed inside the container to be opened; under the indirect contingency, the therapist held the reinforc er and delivered it to the participant upon task completion. One participan t immediately performed the task at 100% accuracy under both contingencies. Three participants showed either more immediate or larger improvements in performance under the direct contingency. The remaining 2 participants show ed improved performance only under the direct reinforcement contingency. Da ta taken on the occurrence of "irrelevant" behaviors under the indirect con tingency (e.g., reaching for the reinforcer instead of performing the cask) provided some evidence that these behaviors may have interfered with task performance and that their occurrence was a function of differential stimul us control.