By David George Gordon
Special to ABCNEWS.com
Is there such a thing as free will?
Paul Grobstein sought to answer this philosophical question by feeding
a batch of lab-raised leopard frogs.
Presented with a live mealworm, each of the frogs took a slightly different
approach — hopping left, right or straight ahead before scarfing the
wriggling snack down.
“The frogs were following what is commonly known as the Harvard Law of
Animal Behavior,” says Grobstein, a professor of biology at Bryn Mawr
College in Pennsylvania.
“Under carefully controlled experimental circumstances, an animal does what
it damned well pleases,” he chuckles.
Road Map of Nerves
As a graduate student in the 1970s, Grobstein spent his days tracing the
circuitry of the nervous system.
“Back then, the idea was that human behavior was directed by the
arrangement of neurons in the brain,” he explains. “If you knew the wiring
diagram, you could hypothetically predict the behavior that would follow.”
Most scientists believed the wiring diagram was largely determined by
genetic information. Later, says Grobstein, they realized that life
experiences also affect the diagram and shape human behavior.
However, as Grobstein’s frog research — and the Harvard Law of Animal
Behavior — have shown, it’s not nearly as simple as that.
“If the only things that matter are the genome and experience, then a frog
should do the same thing every time it’s exposed to the same stimulus,” the biologist suggests.
The reason a frog (or a person) responds differently to an external
stimulus can be traced to what Grobstein calls “intrinsic variability”
— the ever changing state of the nervous system.
“The system is not designed to give a single ‘right’ response,” he says. “Rather, it’s designed to explore, to try things out. By doing
things differently, you can discover new things.”
Here’s how it works:
The unconscious part of the mind reacts to a stimulus and presents its finding to the
conscious part. The conscious part can either accept this
finding or reject it and request another.
“And for me, that process is a reasonably satisfying description of free
will,” Grobstein says.
Not Everyone’s a Believer
Grobstein’s thoughts about frogs and free will have been posted on his Serendip Web site, to mixed reviews from his
peers.
“The issue of free will is not something that most academics regard as
scientific,” he admits.
Still, his way of looking at a things could have important social
implications. In a court of law, for example, it’s often necessary to
establish whether a defendant was responsible for whatever he did.
“If what I’m saying makes sense, then someone is responsible for their
behavior only if their brain is organized in such a way that allows them to
veto a particular perception and ask for another one,” Grobstein says.
“It’s not hard to imagine how things such as brain damage could interfere
with personal responsibility and free will.”
Grobstein’s views could also influence life in the college classroom.
“Instead of telling students there’s a right way to see things, we should
be helping them maximize the number of ways to see things,” the
free-thinking frog philosopher says.
David George Gordon’s column appears every Friday. His latest book, The Eat-A-Bug Cookbook, is published by Ten Speed Press.
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S U M M A R Y
Behavior, frog or human, is far from predictable
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Michael Barbosa, for alerting us to www.trepan.com — a nicely designed site
devoted to trepanation — an ancient technique to release evil spirits by
knocking a hole in the skull. (Do not try this at home.)
