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.