Benjamin Libet; pioneer in studies of free will
Hyfler/Rosner
August 18, 2007 Saturday
FINAL Edition
Benjamin Libet - UCSF pioneer in studies of free will
BYLINE: David Perlman, Chronicle Science Editor
Benjamin Libet, a distinguished neurophysiologist whose
pioneering studies of the human brain explored the nature of
free will and revealed unsuspected links between the
conscious and unconscious aspects of action and awareness,
has died at his home in Davis at age 91.
For nearly 50 years, Dr. Libet was a professor of physiology
at UCSF, and in his laboratory there conducted a series of
major experiments - working first with nerve cells in
rabbits in an effort to understand how chemicals known as
neurotransmitters act in concert to lay down memory traces -
and later with human volunteers, including one of his four
children.
He summed up his conclusions after a lifetime of research in
his book called "Mind Time - The Temporal Factor in
Consciousness," published by Harvard University Press three
years ago.
It was widely praised by other brain researchers, and Dr.
Robert W. Doty, professor of Neurobiology and Anatomy at the
University of Rochester, said of it:
"Benjamin Libet's discoveries are of extraordinary interest.
His is almost the only approach yet to yield any credible
evidence of how conscious awareness is produced by the
brain. Libet's work is unique, and speaks to questions asked
by all humankind."
Dr. Libet also edited a collection of the most important
groundbreaking research papers that he and his many
colleagues published in scientific journals. The volume,
called "Neurophysiology of Consciousness," was published in
1993 by the Swiss international firm Birkhauser Verlag.
One of Dr. Libet's colleagues during some of his early
research at UCSF was the late Dr. Bertram W. Feinstein, a
San Francisco neurosurgeon who treated epilepsy patients by
stimulating their brain circuitry and recording the
responses through deep-seated electrodes.
Dr. Libet measured the response time between the moment the
brain of a patient was stimulated and the time the patient
became consciously aware of the stimulus. He found there was
a consistent half-second delay between the patients'
unconscious reaction and their conscious awareness of the
stimulus.
As Dr. Libet later wrote in the journal Brain Research
Bulletin, "That discovery led to further studies ... and to
profound inferences for the nature of conscious subjective
experience. It formed the basis of that highlight of my
work."
He continued his work with even more experiments to refine
his theories of mind, brain and consciousness, and among his
many volunteer subjects was Gayla Libet, his youngest
daughter who is now an Oakland attorney. Those experiments
also involved using electrodes to measure the response times
of the brain, and he found, for example, that when a
volunteer was instructed to move a finger, the brain
unconsciously initiated the movement even before the
volunteer was aware that the finger had begun moving.
To many philosophers this seemed to indicate that "free
will" might not exist in humans at all, but Dr. Libet
disagreed. When his experiments showed that if his subjects
were told not to move a finger, or to stop moving it, their
conscious will would maintain complete control - "could veto
it and block performance of the act," as he described it.
"These discoveries have profound implications for the nature
of free will, for individual responsibility and guilt," he
wrote.
Dr. Libet was born in Chicago on April 16, 1916, and earned
his doctorate at the University of Chicago when he was only
23. He taught and began his research at universities in
Albany, N.Y., and Philadelphia before joining the UCSF
faculty in 1950. He and his wife moved to Davis seven years
ago.
A funeral was held at the Davis Cemetery in Davis on July
30.
Surviving are his wife of 68 years, Fay Libet; sons, Julian,
a psychologist in Charleston, S.C., and Ralph, a physician
in Sacramento; and daughters, Moreen, an anthropologist in
Davis, and Gayla of Oakland.
Hoodude
> Dr. Libet measured the response time between the moment the
> brain of a patient was stimulated and the time the patient
> became consciously aware of the stimulus. He found there was
> a consistent half-second delay between the patients'
> unconscious reaction and their conscious awareness of the
> stimulus.
Like, Dude, that is so totally awesome. Is that with like a gravity
bong, or something?
Let's go get baked until we reach unconscious awareness of the
stimulus.
--
Ahh, gimme the crack of the doo-dad gew-gaw
- Professor Longhair