The study by Nixon and Parsons (1991) predicted that availability deficits would be characterized by a subject’s inability to identify the relevant variable in the task and that efficiency deficits would be characterized by the inclusion of irrelevant variables in describing the reason for the plant’s outcome. The results indicated that although no group differences existed in the ability to predict correctly the fate of the unseen plant, the alcoholics experienced significantly greater difficulty than the control subjects in their ability to isolate the relevant variable, having more problems with ignoring irrelevant information in their explanations of the plant’s outcome. The researchers concluded that this deficit was indicative of efficiency impairments within the knowledge-information store. Although it is premature to link deficits in efficiency with any particular brain system, it is hoped that research will bring these two areas of investigation together.
