The second prediction hinges on the considerable evidence from a separate line of research into possible right-hemisphere brain dysfunction in alcoholics (see Oscar-Berman 1992). Like patients with damage to the right hemisphere, alcoholics typically perform poorly on visuospatial tasks. The similarity in performance between alcoholics and patients with right-hemisphere damage led researchers to hypothesize that right-brain functions are more vulnerable than left-brain functions to the effects of alcohol. Thus, the increased vulnerability hypothesis predicts that older alcoholics, the group in whom the effects of aging and alcoholism are combined, would show deficits out of proportion to their age on specialized tests of right-hemisphere functioning.7 This was not the case in the study just described (Ellis 1990). The results of numerous other studies examining right-hemisphere functional decline in relation to alcoholism and aging have not been sufficiently consistent to resolve the premature aging issue (for a review, see Ellis and Oscar-Berman 1989).
