 |
As
a college student, B. F. Skinner gave little thought to psychology. He
had hoped to become a novelist, and majored in English. Then, in 1927,
when he was twenty-three, he read an essay by H. G. Wells about the
Russian physiologist Ivan Pavlov. The piece, which appeared in the Times Magazine,
was ostensibly a review of the English translation of Pavlov’s
“Conditioned Reflexes: An Investigation of the Physiological Activity of
the Cerebral Cortex.” But, as Wells pointed out, it was “not an easy
book to read,” and he didn’t spend much time on it. Instead, Wells
described Pavlov, whose systematic approach to physiology had
revolutionized the study of medicine, as “a star which lights the world,
shining down a vista hitherto unexplored.”
That
unexplored world was the mechanics of the human brain. Pavlov had
noticed, in his research on the digestive system of dogs, that they
drooled as soon as they saw the white lab coats of the people who fed
them. They didn’t need to see, let alone taste, the food in order to
react physically. Dogs naturally drooled when fed: that was, in Pavlov’s
terms, an “unconditional” reflex. When they drooled in response to a
sight or sound that was associated with food by mere happenstance, a
“conditional reflex” (to a “conditional stimulus”) had been created.
Pavlov had formulated a basic psychological principle—one that also
applied to human beings—and discovered an objective way to measure how
it worked.
Skinner was enthralled. Two years after reading the Times Magazine
piece, he attended a lecture that Pavlov delivered at Harvard and
obtained a signed picture, which adorned his office wall for the rest of
his life. Skinner and other behaviorists often spoke of their debt to
Pavlov, particularly to his view that free will was an illusion, and
that the study of human behavior could be reduced to the analysis of
observable, quantifiable events and actions.
But
Pavlov never held such views, according to “Ivan Pavlov: A Russian Life
in Science” (Oxford), an exhaustive new biography by Daniel P. Todes, a
professor of the history of medicine at Johns Hopkins School of
Medicine. In fact, much of what we thought we knew about Pavlov has been
based on bad translations and basic misconceptions. That begins with
the popular image of a dog slavering at the ringing of a bell. Pavlov
“never trained a dog to salivate to the sound of a bell,” Todes writes.
“Indeed, the iconic bell would have proven totally useless to his real
goal, which required precise control over the quality and duration of
stimuli (he most frequently employed a metronome, a harmonium, a buzzer,
and electric shock).”
Pavlov is perhaps best
known for introducing the idea of the conditioned reflex, although Todes
notes that he never used that term. It was a bad translation of the
Russian uslovnyi, or “conditional,” reflex. For Pavlov, the
emphasis fell on the contingent, provisional nature of the
association—which enlisted other reflexes he believed to be natural and
unvarying. Drawing upon the brain science of the day, Pavlov understood
conditional reflexes to involve a connection between a point in the
brain’s subcortex, which supported instincts, and a point in its cortex,
where associations were built. Such conjectures about brain circuitry
were anathema to the behaviorists, who were inclined to view the mind as
a black box. Nothing mattered, in their view, that could not be
observed and measured. Pavlov never subscribed to that theory, or shared
their disregard for subjective experience. He considered human
psychology to be “one of the last secrets of life,” and hoped that
rigorous scientific inquiry could illuminate “the mechanism and vital
meaning of that which most occupied Man—our consciousness and its
torments.” Of course, the inquiry had to start somewhere. Pavlov
believed that it started with data, and he found that data in the saliva
of dogs.
Pavlov’s research originally had
little to do with psychology; it focussed on the ways in which eating
excited salivary, gastric, and pancreatic secretions. To do that, he
developed a system of “sham” feeding. Pavlov would remove a dog’s
esophagus and create an opening, a fistula, in the animal’s throat, so
that, no matter how much the dog ate, the food would fall out and never
make it to the stomach. By creating additional fistulas along the
digestive system and collecting the various secretions, he could measure
their quantity and chemical properties in great detail. That research
won him the 1904 Nobel Prize in Physiology or Medicine. But a dog’s
drool turned out to be even more meaningful than he had first imagined:
it pointed to a new way to study the mind, learning, and human behavior.
More >>
No hay comentarios:
Publicar un comentario