Although the right hemisphere model is supported by research as it relates to alcoholism and to normal aging separately, several weaknesses of this model should be noted (for review, see Ellis and Oscar-Berman 1989). First, the findings by Ellis (1990) mentioned above have not been reproduced, and the majority of the evidence does not strongly support either version of the premature aging hypothesis in relation to this model. Second, this model is descriptive rather than explanatory. That is, no explanation is provided for why the right hemisphere of the brain per se would be differentially sensitive to the effects of alcoholism and aging. A third problem with this model is that alcoholics have been shown to manifest verbal cognitive deficits (which are associated with the left brain) in addition to nonverbal patterns of deficits when sensitive tasks are used. Thus, when differences are found between alcoholics’ performance on verbal and nonverbal tasks, it may be explained simply by the specific demands of the tasks rather than by solely right brain deficits.
