1913–1994 · neurobiologist, Chicago and Caltech

he American neurobiologist Roger Wolcott Sperry worked at Chicago and from 1954 at Caltech. He shared the 1981 Nobel Prize, with Hubel and Wiesel, for work on the functional specialisation of the cerebral hemispheres.

what he did

He first showed that nerve fibres in frogs and fish regrow to their old targets even when that makes the animal behave wrongly, and proposed chemical tags to explain it. Then, with Michael Gazzaniga and the surgeon Joseph Bogen, he tested patients whose corpus callosum had been cut to control epilepsy (Gazzaniga, Bogen & Sperry, 1962). Shown something only to the right hemisphere, a patient could pick it out with the left hand while saying, through the left hemisphere, that he had seen nothing. Sperry concluded that each hemisphere could have a conscious mind of its own (Sperry, 1968) [paraphrase, not a quotation].

what is argued about

How divided the split brain really is. Newer studies of a few patients found unified awareness with divided perception (Pinto et al., 2017), and the reply was quick (Volz & Gazzaniga, 2017); a later review argues for a middle view (de Haan et al., 2020). Gazzaniga's "interpreter", the left hemisphere inventing reasons for what the right one did (Gazzaniga, 2005), is the part most often borrowed for talk about machines that explain themselves.

why he is here

Split-brain patients confabulate fluently and sincerely: see hallucination and the Libet archive page.

in the tour: the room called "Two halves" has a placard called "Cut" ···

Primary works and sources

1. Gazzaniga, Bogen & Sperry (1962). Some functional effects of sectioning the cerebral commissures in man. Proceedings of the National Academy of Sciences. doi:10.1073/pnas.48.10.1765
2. Sperry (1968). Hemisphere deconnection and unity in conscious awareness. American Psychologist. doi:10.1037/h0026839
3. Pinto et al. (2017). Split brain: divided perception but undivided consciousness. Brain. doi:10.1093/brain/aww358
4. Volz & Gazzaniga (2017). Interaction in isolation: 50 years of insights from split-brain research. Brain. doi:10.1093/brain/awx139
5. de Haan et al. (2020). Split-Brain: What We Know Now and Why This is Important for Understanding Consciousness. Neuropsychology Review. doi:10.1007/s11065-020-09439-3
6. Gazzaniga (2005). Forty-five years of split-brain research and still going strong. Nature Reviews Neuroscience. doi:10.1038/nrn1723

see also

	archive: Libet — another case of explaining after the fact
	the nervous system
	Santiago Ramón y Cajal