Gazzaniga: An interview with the neuroscientist and professor of psychology known for his studies, and stories, about the brain's split personality.
MichaelMichael S. Gazzaniga
This is the fourth in an occasional series of articles and videos about leaders in science.
Everything was ready. The electrode was in place, threaded between the two hemispheres of a living cat’s brain; the instruments were tuned to pick up the chatter passing from one half to the other. The only thing left was to listen for that electronic whisper, the brain’s own internal code.
The amplifier hissed — the three scientists expectantly leaning closer — and out it came, loud and clear.
“We all live in a yellow submarine, yellow submarine, yellow submarine ....”
“The Beatles’ song! We somehow picked up the frequency of a radio station,” recalled Michael S. Gazzaniga, chuckling at the 45-year-old memory. “The brain’s secret code. Yeah, right!”
University of California, Santa Barbara, is best known for a dazzling series of studies that revealed the brain’s split personality, the division of labor between its left and right hemispheres. But he is perhaps next best known for telling stories, many of them about blown experiments, dumb questions and other blunders during his nearly half-century career at the top of his field.
Dr. Gazzaniga, 71, now a professor of psychology at theNow, in lectures and a new book, he is spelling out another kind of cautionary tale — a serious one, about the uses of neuroscience in society, particularly in the courtroom.
Brain science “will eventually begin to influence how the public views justice and responsibility,” Dr. Gazzaniga said at a recent conference here sponsored by the Edge Foundation.
And there is no guarantee, he added, that its influence will be a good one.
For one thing, brain-scanning technology is not ready for prime time in the legal system; it provides less information than people presume.
For another, new knowledge about neural processes is raising important questions about human responsibility. Scientists now know that the brain runs largely on autopilot; it acts first and asks questions later, often explaining behavior after the fact. So if much of behavior is automatic, then how responsible are people for their actions?
Who’s driving this submarine, anyway?
In his new book, “Who’s in Charge? Free Will and the Science of the Brain,” being published this month by Ecco/HarperCollins, Dr. Gazzaniga (pronounced ga-ZAHN-a-ga) argues that the answer is hidden in plain sight. It’s a matter of knowing where to look.
The Split Brain
He began thinking seriously about the nature of responsibility only after many years of goofing off.
Mike Gazzaniga grew up in Glendale, Calif., exploring the open country east of Los Angeles and running occasional experiments in his garage, often with the help of his father, a prominent surgeon. It was fun; the experiments were real attempts to understand biochemistry; and even after joining the Alpha Delta Phi fraternity at Dartmouth (inspiration for the movie “Animal House”), he made time between parties and pranks to track who was doing what in his chosen field, brain science.
California Institute of Technologysuggesting that in animals, developing nerve cells are coded to congregate in specific areas in the brain. This work was captivating for two reasons.
In particular, he began to follow studies at theFirst, it seemed to contradict common wisdom at the time, which held that specific brain functions like memory were widely — and uniformly — distributed in the brain, not concentrated in discrete regions.
Second, his girlfriend was due to take a summer job right there near Caltech.
He decided to write a letter to the director of the program, the eminent neurobiologist Roger Wolcott Sperry (emphasizing reason No. 1). Could Dr. Sperry use a summer intern? “He said sure,” Dr. Gazzaniga said. “I always tell students, ‘Go ahead and write directly to the person you want to study with; you just never know.’ ”
At Caltech that summer after his junior year, he glimpsed his future. He learned about so-called split-brain patients, people with severe epilepsy who had surgery cutting the connections between their left and right hemispheres. The surgery drastically reduced seizures but seemed to leave people otherwise unaffected.
Back at Dartmouth, he couldn’t stop thinking about it: Totally unaffected? Combing the literature, he found that the best attempt to detect an effect had found no changes in thinking or perception among 26 patients who had had the surgery at the University of Rochester.
Could that be possible? Mr. Gazzaniga was so eager to test the patients’ perceptions himself that he wrote another letter, this time to the surgeon — and got permission to do so.
“It’s spring break, I get all my gear together, I get all the way over there, and the guy changes his mind,” Dr. Gazzaniga said. “Like, ‘Hey, buddy, go home!’ ”
After graduating, he headed straight for Caltech.
“It wasn’t just ambition, it was something else — he was gutsy,” said Mitch Glickstein, who was in Dr. Sperry’s lab at the time and is completing a book, “Neuroscience: A Historical Introduction.” “Here’s this junior in college, he knows all about the split-brain patients, and he’s ready to do original research. At 20 years old.”
Nobel Prizecontenders. Here’s Richard Feynman, the physicist, parking himself in the lab unannounced and making wisecracks about the experiments. There’s Dr. Sperry, annoyed, wondering how to one-up Dr. Feynman. One afternoon Dr. Sperry’s young student scrambled out into the hallway on all fours after an escaped lab animal and nearly kneecapped Linus Pauling, the eminent chemist. (“Why don’t you try anesthetizing a bowl of jelly instead?” Dr. Pauling remarked icily.)
Caltech in those days was like a frat house forAnd then there were the experiments, each one a snapshot into the dark box of the brain. In the early 1960s, Dr. Gazzaniga, then a graduate student, teamed with Dr. Sperry and Dr. Joseph Bogen, a brain surgeon, to publish a string of reports that dramatically demonstrated hemispheric specialization in humans.
The researchers devised a way to flash a picture of a bicycle to the right hemisphere alone. When split-brain patients were asked what they saw, they replied, “Nothing”: Because of the severed connection, the left hemisphere, where language is centered, got no visual input and no information from the right hemisphere. So the right hemisphere — which “saw” the bike — had no language to name it.
But here was the kicker: The right hemisphere could direct the hand it controls to draw the bicycle.
In other studies, the three scientists showed that the right hemisphere could also identify objects by touch, correctly selecting, say, a toothbrush or a spoon by feel after seeing the image of one.
The implications were soon clear. The left hemisphere was the intellectual, the wordsmith; it could be severed from the right without loss of I.Q. The right side was the artist, the visual-spatial expert.
The findings demolished the theory that specific functions were widely and uniformly supported in the brain. It also put “left brain/right brain” into the common language, as shorthand for types of skills and types of people. Still, in a field defined by incremental, often arcane advances, the Caltech team had achieved a moon shot.
Dr. Gazzaniga, now all of 25, could write his own ticket. He soon had a grant for a study to record the electronic chatter between the two hemispheres in the brain of a cat.
The Interpreter
The Beatles song that surged through the receiver in that experiment provided Dr. Gazzaniga with something almost as valuable as insight: a good story. Yet it also served as a rude reminder that he and his colleagues were missing something important in their assumptions about the brain.
“The question, ultimately, was why?” Dr. Gazzaniga said. “Why, if we have these separate systems, is it that the brain has a sense of unity?”
Even as he built his early triumph into a career, moving from Caltech to U.C. Santa Barbara and eventually to Dartmouth, with several stops along the way, the same question hung in the air, without a satisfactory answer. In the late 1970s, with the psychologist and linguist George A. Miller, he founded the field of cognitive neuroscience, a marriage of psychology and biology aimed at solving just such puzzles.
It didn’t happen, at least not quickly. In the decades to follow, brain scientists found that the left brain-right brain split is only the most obvious division of labor; in fact, the brain contains a swarm of specialized modules, each performing a special skill — calculating a distance, parsing a voice tone — and all of them running at the same time, communicating in widely distributed networks, often across hemispheres.