Cognitive asymmetry and dreaming: lack of relationship.

The present study investigated the relationship between cognitive laterality and dream recall, dream characteristics, and eye movement density in rapid eye movement (REM) sleep. Fifty-two right-handed males, age 20-30 years, were tested on a six-test battery of which three tests measure right hemisphere function and three tests measure left hemisphere function. Based on their performance, 14 subjects were selected for a sleep laboratory study. Each spent 3 experimental nights in the laboratory during which they were awakened from REM sleep for dream reports. Dream reports were scored for bizarreness, emotions, visual elements, and overall "dreamlike" versus "thoughtlike" character. Subjects were awakened from 123 REM periods, of which 96 yielded positive dream reports (78.04%). Neither the rate of recall nor the four evaluation scores were correlated with the laterality scores that were constructed from the six-test battery. Eye movement density during REM sleep was significantly positively correlated with the total performance of the two hemispheres. These results do not support the alleged lateralization of dreaming. In agreement with recent reports in the literature, it is concluded that dreaming cannot be seen as a "right hemisphere" function.