Researchers have hypothesized that right-brain functions are more vulnerable to alcoholism’s effects than are left-brain functions (for a review, see Ellis and Oscar-Berman 1989). They have based this right hemisphere model on findings that alcoholics generally show a steeper decline on nonverbal tasks than on verbal tasks on most IQ tests (figure 1). For example, on a common IQ test, the Wechsler Adult Intelligence Scale–Revised (WAIS–R; Wechsler 1981), alcoholics often perform abnormally poorly on the digit symbol, object assembly, and block design subtests, all of which assess nonverbal information processing (Ellis 1990; see also the article on cognitive assessment by Nixon, pp. 97–103). Similar deficits appear when both nonverbal and verbal materials are used in tasks that assess mental functions such as memory and attention. These types of cognitive deficits reported in long-term chronic alcoholics resemble the deficits observed in patients with damage to the right hemisphere of the brain that is unrelated to alcoholism.
