Hemispheric specialization and creativity.

The results of an experimental study on commissurotomy (split-brain) patients and normal control subjects illuminate the difference in creativity. The surgical disconnection of transcallosal interhemispheric exchange and of any access or communication between the two hemispheres creates in commissurotomy patients an outstanding lack of creativity which could be demonstrated on a lexical, sentential, global, affective, and EEG-analysis level. In contrast to split-brain or alexithymic people, expressive-creative persons verbalized their presentational symbolization and imagery of the right hemisphere which was transformed via corpus callosum to the left hemisphere, called symbollexia. Thus, creativity can be understood as the opposite of alexithymia. The hypothetical concept of creativity as hemispheric bisociation was supported by EEG findings, suggesting an inhibition and lack of inner speech between the two language centers in alexithymic people versus a higher interhemispheric coherence level in expressive-creative persons. Further on, the difference of expressed feelings of anxiety and hostility suggests a restrictive set of rules and of early superego components in commissurotomy patients in contrast to expressive-creative people who empathically experience and verbalize their anxiety about death and are open to the experience of their being in the world as an act of creation. Finally, the vignette of a creative patient whose left hemisphere was overflooded by affects and imagery, expressed in her pictures, illuminates the importance of a balanced transcallosal symbollexia and hemispheric bi-sociation in psychotherapy.