Chapter 6 : The MIND-BODY Problem
The Emergence of Mind from Brain
The Ethical Brain
|By CARL ZIMMER
Dr. Michael Gazzaniga, the director of the Center for Cognitive Neuroscience at Dartmouth. In the 1980's he helped found cognitive neuroscience, a discipline designed to find out how the mind emerges from the brain. The Ethical Brain" one of the first works of neuroethics, the intersection of ethics and neuroscience.
"It's a new lens for looking at these issue, and he's the first person to focus it and get a sharp picture," said Dr. Judy Illes, director of the program in neuroethics at the Stanford Center for Biomedical Ethics.
In the late 1970's, Dr. Gazzaniga rallied his colleagues
to turn this sort of research into a full-fledged
field, which they called cognitive neuroscience. He helped organize a
scientific society and started a journal, and every
five years he edits a gigantic tome summarizing what scientists know about
how the mind emerges from the brain. "More than anyone else, Mike Gazzaniga
created the field of cognitive neuroscience," said Dr.
George Miller, a cognitive psychologist at Princeton.
For example, he thinks it is wrong to use neuroimaging as
a lie detector or as a tool to determine whether
criminals are responsible for their crimes. "It shouldn't be dragged into
the courtroom," he said. "I think
Neuroscience's biggest contribution to ethics, Dr.
Gazzaniga predicted, is only just emerging: a
biological explanation of morality. "In the next 20 years, we're probably
going to define why our species seems to
Current research suggests that this moral compass appears
to be the product of the human brain's intricate
circuitry for understanding other people's thoughts and feelings. Just
looking at pictures of people
Dr. Gazzaniga argues that when we experience these
feelings, the brain's interpreter produces rational
explanations for them. The particular explanation it produces depends on a
person's particular upbringing.
But, he said, "the basic reason you don't kill is because your brain tells you it's not a good idea to kill."
May 10, 2005
HANOVER, N.H. - If you walk into the office of a scientist, chances are you'll see a white board hanging on the wall covered in scrawls. A molecular biologist's white board might be covered by hideous tangles of protein chains. A geophysicist might doodle India crashing into southern Asia.
The scribbles of Dr. Michael Gazzaniga, the director of the Center for Cognitive Neuroscience at Dartmouth, are more metaphysical. Neuroscience is even shedding light on how moral beliefs take shape in our brain.
Dr. Gazzaniga studied this effect in humans. Surgeons sometimes cut the corpus callosum of people with severe epilepsy to reduce their seizures. In 1960, Dr. Gazzaniga examined one such patient, known as W. J. He found that human hemispheres became isolated as well. W. J. could put together a simple jigsaw puzzle with either his left or right hand, for example, but not both.
The hemispheres also displayed different strengths and weaknesses. W. J. could read complicated writing with his right eye, but with his left eye he gave only a blank response.
"Boom - the whole thing unfolds in front of your eyes," Dr. Gazzaniga said. "It was a great moment. I'm not sure I've had such a great moment of a scientific nature since."
Studies on split-brain patients have dominated Dr. Gazzaniga's work ever since. In the 1970's, he and his colleagues reported that the left hemisphere acts as an interpreter, creating theories to makes sense of a person's experiences.
Their first clue came from an experiment Dr. Gazzaniga carried out with Dr. Joseph LeDoux, now at New York University. A patient called P. S. was shown a picture, and was then asked to choose a related image from a set of other pictures. What P. S. didn't know was that he was being shown a different image in each eye.
Dr. Gazzaniga and Dr. LeDoux showed P. S. a picture of a chicken claw in his right eye and a snow-covered house in the left eye. P. S. pointed to a chicken with his right hand and a snow shovel with his left.
"I'll never forget the day we got around to asking P. S., 'Why did you do that?' " said Dr. Gazzaniga. "He said, 'The chicken claw goes with the chicken.' That's all the left hemisphere saw. And then he looks at the shovel and said, 'The reason you need a shovel is to clean out the chicken shed.' "
Dr. Gazzaniga hypothesized that P. S.'s left hemisphere made up a story to explain his actions, based on the limited information it received. Dr. Gazzaniga and his colleagues have carried out the same experiment hundreds of times since, and the left hemisphere has consistently acted this way.
"The interpreter tells the story line of a person," Dr. Gazzaniga said. "It's collecting all the information that is in all these separate systems that are distributed through the brain." While the story feels like an unfiltered picture of reality, it's just a quickly-thrown-together narrative.
Copyright 2005 The New York Times Company
|June 19, 2005
'The Ethical Brain': Mind Over Gray Matter
a book review by SALLY SATEL
As director of the Center of Cognitive Neuroscience at Dartmouth College and indefatigable author of five previous books on the brain for the general reader alone, Gazzaniga is less interested in delivering verdicts on bioethical quandries -- should we clone? tinker with our babies' I.Q.? -- than in untangling how we arrive at moral and ethical judgments in the first place.
Take the issue of raising intelligence by manipulating genes in test-tube embryos. Gazzaniga asks three questions. Is it technically possible to pick out ''intelligence genes''? If so, do those genes alone determine intelligence? And finally, is this kind of manipulation ethical? ''Most people jump to debate the final question,'' he rightly laments, ''without considering the implications of the answers to the first two.'' Gazzaniga's view is that someday it will be possible to tweak personality and intelligence through genetic manipulation. But because personhood is so significantly affected by factors like peer influence and chance, which scientists can't control, we won't be able to make ''designer babies,'' nor, he believes, will we want to.
Or consider what a ''smart pill'' might do to old-fashioned sweat and toil. Gazzaniga isn't especially worried. Neither a smart pill nor genetic manipulation will get you off the hook: enhancement might enable you to grasp connections more easily; still, the fact remains that ''becoming an expert athlete or musician takes hours of practice no matter what else you bring to the task.''
But there are ''public, social'' implications. Imagine basketball stars whose shoes bear the logo not of Nike or Adidas but of Wyeth or Hoffman-La Roche, ''touting the benefits of their neuroenhancing drugs.'' ''If we allow physical enhancements,'' Gazzaniga argues, ''some kind of pharmaceutical arms race would ensue and the whole logic of competition would be neutralized.'' Gazzinga has no doubt that ''neuroscience will figure out how to tamper'' with neurochemical and genetic processes. But, he says, ''I remain convinced that enhancers that improve motor skills are cheating, while those that help you remember where you put your car keys are fine.''
So where, as Gazzaniga asks, ''do the hard-and-fast facts of neuroscience end, and where does ethics begin?'' In a chapter aptly called ''My Brain Made Me Do It,'' Gazzaniga puts the reader in the jury box in the case of a hypothetical Harry and ''a horrible event.'' This reader confesses impatience with illuminated brain scans routinely used to show that people ''addicted'' to drugs -- or food, sex, the Internet, gambling -- have no control over their behavior. Refreshingly, Gazzaniga declares ''the view of human behavior offered by neuroscience is simply at odds with this idea.''
''Just as optometrists can tell us how much vision a person has (20/20 or 20/40 or 20/200) but cannot tell us when someone is legally blind,'' he continues, ''brain scientists might be able to tell us what someone's mental state or brain condition is but cannot tell us (without being arbitrary) when someone has too little control to be held responsible.''
Last year, when the United States Supreme Court heard arguments against the death penalty for juveniles, the American Medical Association and other health groups, including psychiatrists and psychologists, filed briefs arguing that children should not be treated as adults under the law because in normal brain development the frontal lobe -- the region of the brain that helps curb impulses and conduct moral reasoning -- of an adolescent is still immature. ''Neuroscientists should stay in the lab and let lawyers stay in the courtroom,'' Gazzangia writes.
Moving on to the provocative concept of ''brain privacy,'' Gazzaniga describes brain fingerprinting -- identifying brain patterns associated with lying -- and cautions that just like conventional polygraph tests, these ''much more complex tests . . . are fraught with uncertainties.'' He also provides perspective on the so-called bias tests increasingly used in social science and the law, like one recently described in a Washington Post Magazine article. Subjects were asked to pair images of black faces with positive or negative words (''wonderful,'' ''nasty''); if they pressed a computer key to pair the black face with a positive word several milliseconds more slowly than they paired it with a negative word, bias was supposed. The unfortunate headline: ''See No Bias: Many Americans believe they are not prejudiced. Now a new test provides powerful evidence that a majority of us really are. Assuming we accept the results, what can we do about it?''
Nonsense, Gazzaniga would say. Human brains make categories based on prior experience or cultural assumptions. This is not sinister, it is normal brain function -- and when experience or assumptions change, response patterns change. ''It appears that a process in the brain makes it likely that people will categorize others on the basis of race,'' he writes. ''Yet this is not the same thing as being racist.'' Nor have split-second reactions like these been convincingly linked to discrimination in the real world. ''Brains are automatic, rule-governed, determined devices, while people are personally responsible agents,'' Gazzaniga says. ''Just as traffic is what happens when physically determined cars interact, responsibility is what happens when people interact.''
Clearly, Gazzaniga is not a member of the handwringer school, like some of his fellow members of the President's Council on Bioethics. At the same time, his faith in our ability to regulate ourselves is touching. He notes that sex selection appears to be producing alarmingly unbalanced ratios of men to women in many countries. ''Tampering with the evolved human fabric is playing with fire,'' he writes. ''Yet I also firmly believe we can handle it. . . . We humans are good at adapting to what works, what is good and beneficial, and, in the end, jettisoning the unwise.''
Gazzaniga looks to the day when neuroethics can derive ''a brain-based philosophy of life.'' But ''The Ethical Brain'' does not always make clear how understanding brain mechanisms can help us deal with hard questions like the status of the embryo or the virtues of prolonging life well over 100 years. And occasionally the book reads as if technical detail has been sacrificed for brevity.
A final, speculative section, ''The Nature of Moral Beliefs and the Concept of Universal Ethics,'' explores whether there is ''an innate human moral sense.'' The theories of evolutionary psychology point out, Gazzaniga notes, that ''moral reasoning is good for human survival,'' and social science has concluded that human societies almost universally share rules against incest and murder while valuing family loyalty and truth telling. ''We must commit ourselves to the view that a universal ethics is possible,'' he concludes. But is such a commitment important if, as his discussion suggests, we are guided by a universal moral compass?
Still, ''The Ethical Brain'' provides us with cautions -- prominent among them that ''neuroscience will never find the brain correlate of responsibility, because that is something we ascribe to humans -- to people -- not to brains. It is a moral value we demand of our fellow, rule-following human beings.'' This statement -- coming as it does from so eminent a neuroscientist -- is a cultural contribution in itself.
Sally Satel is a psychiatrist and resident scholar at the American Enterprise Institute and a co-author of ''One Nation Under Therapy: How the Helping Culture Is Eroding Self-Reliance.''
Copyright 2005 The New York Times Company
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