The experimental analysis of human operant behavior following traumatic brain injury

Traumatic brain injury (TBI) may produce deficits in discriminating and res ponding appropriately to consequences. Commonly, insensitivity to consequen ces is attributed to deficits in cognitive processes, particularly executiv e functioning. The present investigation examined the hypothesis that TBI m ay reduce control exerted by reinforcers over behavior. Results of basic op erant research on reinforcement processes with individuals with TBI may hav e clinical value for understanding and ultimately remediating deficits asso ciated with TBI. In experiment 1, responding by adults with TBI and non-inj ured controls was investigated under reinforcement contingencies that diffe rentially reinforced responding and the absence of responding within sessio ns. Results showed that most TBI subjects obtained lower reinforcement rate s than control subjects, especially under contingencies requiring the absen ce of responding. In experiment 2, results showed that the addition of stim uli correlated with reinforcement improved one subject's performance. These results suggest that TBI may differentially reduce sensitivity to response -reinforcer contingencies and some environmental changes may increase sensi tivity. Results also suggest parallels between deficits in executive functi oning and deficits in operant behavior. Copyright (C) 2000 John Wiley & Son s, Ltd.