| Popis: |
Two hypotheses concerning the psychological effects of marihuana are proposed: (a) that the process of becoming “high” on marihuana consists, in part, of shifting into a new cognitive style or mode which involves less reliance on analytical, sequential, verbal processing, and more reliance on synthetic, holistic, imagistic processing; (b) that one of the ways that marihuana produces this shift is by decreasing left, and increasing right hemisphere participation in cognitive activities. To test these hypotheses, 25 male subjects were administered a battery of psychological tests which tap either analytic or synthetic (or “mixed”) cognitive processes by means of tasks lateralized either to the left or to the right hemisphere (or both hemispheres). Each subject was tested in both nonintoxicated and intoxicated states, according to a counterbalanced design. A differential pattern of marihuana effects was observed: verbal analytic tasks were impaired, holistic-nonverbal closure tasks were facilitated, and “visualization” tasks showed mixed results. Performance on “low level” perceptual tasks was not affected. To further test the relationship between marihuana effects and brain lateralization, the subject sample was split into a “high lateralized” and a “low lateralized” group, based on nonintoxicated performance on dichotic listening tasks. Separate analyses indicated that “low lateralized” subjects showed no enhancement of closure ability when intoxicated, whereas “high lateralized” subjects showed a strong enhancement of this ability. Further differences in drug effects were also noted, consistent with the hypothesis that an individual’s reaction to marihuana depends, in part, upon his particular pattern of brain lateralization. |
