A lover of fine wine and conversation, Gazzaniga, today a professor of psychology at the University of California, Santa Barbara, is also that rarity: a scientist whose life and work cross over into the humanities.

From his home in Santa Barbara, the author of Tales From Both Sides of the Brain: A Life in Neuroscience talks about where the next big breakthroughs in our understanding of the brain will come from, why a 14-day-old blastocyst isn't a human being, and how he came to meet Groucho Marx.

We worked on a number of patients with severe epilepsy. The surgery they underwent to control their epilepsy allowed us to study each half of the brain separately without one being influenced by