The effects of brain injury on choice and sensitivity to remote consequences: Deficits in discriminating response-consequence relations

Primary objective: One characteristic of some decision-making deficits is a failure to respond adaptively to consequences that follow choices. This investigation examined the sensitivity of choice to remote consequences with a high overall reinforcement rate and proximal consequences with a low overall reinforcement rate. Methods: Three control and three subjects with brain injury made repeated choices between two reinforcement schedules: a fixed time schedule (FT) that delayed reinforcement by 12 seconds, and a progressive time schedule (PT) that progressively increased reinforcement delay by 2 seconds with each consecutive choice and reset to 0 seconds with each choice of the fixed schedule. Switching to the FT schedule at PT 6 seconds maximized overall reinforcement rate. Results: Subjects with brain injury were less sensitive to contingencies and earned less reinforcement relative to controls because switching occurred at lengthy PT delays (delays far exceeding 6 seconds). Conclusions: Some deficits in decision-making and adaptation following injury may reflect a reduction in sensitivity to contingencies.