The effects of brain injury on choice and sensitivity to remote consequences: deficits in discriminating response-consequence relations.
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.
Schlund
Michael W
MW
Kennedy Krieger Institute and Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA. schlund@kennedykrieger.org
D000328:Adult; D001930:Brain Injuries / Q000150:complications / Q000523:psychology*; D003072:Cognition Disorders / Q000209:etiology* / Q000503:physiopathology; D003657:Decision Making; D005260:Female; D006801:Humans; D008297:Male; D008606:Mental Processes; D008875:Middle Aged; D012055:Reinforcement Schedule