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"Long
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May 15, 2007
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Roots of “free will” seen in flies
May 15, 2007
Courtesy Public Library of Science
and World Science staff
Lower
animals are often seen as robotic and programmed in their actions
and reactions. Insects, with their apathetic eyes and stiff
little frames, seem to epitomize these dreary qualities.
But scientists studying fruit flies say they have discovered that
the little bugs have been slandered: they in fact display
considerable spontaneity, and this may be at the
evolutionary root of what we sense as “free will.”
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The fruit fly Drosophila
melanogaster (Courtesy NASA)
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The research could shed light on a centuries-old debate over free will—whether anyone really has
it or whether, instead, mindless movements of atoms in our brains control all
our decisions.
The study appears in the May 16 issue of the research journal PLoS
One.
“Animals and especially insects are usually seen as complex
robots which only respond to external stimuli,” said Björn Brembs
of the Free University Berlin, one of the researchers. When
scientists see animals responding differently to the same
stimuli, they typically ascribe this “to random errors in a
complex brain.”
Using behavior recordings and mathematical analyses, the
researchers found that such variability can’t be due to pure
chance but is generated spontaneously and non-randomly by the
brain.
The results caught computer scientist and co-investigator
Alexander Maye of the University of Hamburg, Germany by
surprise: “I would have never guessed that simple flies who
otherwise keep bouncing off the same window have the capacity
for nonrandom spontaneity if given the chance.”
The researchers tethered fruit flies, Drosophila melanogaster, in
uniform white surroundings and recorded their turning behavior.
The flies in this setup receive no visual cues from the
environment and since they are fixed in space, their turning
attempts have no effect. Thus lacking any input, their behavior
should resemble random noise, similar to a radio tuned between
stations, the investigators reasoned.
However, the analysis found that fly behavior is very
different. Various increasingly complex random computer
models failed to adequately account for fly behavior, the
researchers said.
They
found the source of the spontaneity, they added, after
analyzing the behavior with methods developed by co-authors
George Sugihara and Chih-hao Hsieh of the Scripps Institution of
Oceanography at the University of California San Diego.
“We found that there must be an evolved function in the fly brain
which leads to spontaneous variations in fly behavior,”
Sugihara said. “The results of our analysis indicate a
mechanism which might be common to many other animals and could
form the biological foundation for what we experience as free
will.”
Our subjective notion of “free will” is an oxymoron, Brembs
remarked: the term ‘will’ would not apply if our actions were
completely random and it would not be ‘free’ if they were entirely
determined. So if there is free will, it must be somewhere between
chance and necessity—just where fly behavior lies. “The question
of whether or not we have free will appears to be posed the wrong
way,” said Brembs. “Instead, if we ask ‘how close to free will are we’
one finds that this is precisely where humans and animals
differ.”
The next step will be to use genetics to locate and understand the
brain circuits responsible for the spontaneous behavior,
researchers added. This could lead to the development of robots
with the capacity for spontaneous nonrandom behavior, they
said. It may also help, they predicted, in treating disorders
leading to compromised spontaneous behavioral variability
in humans—such as depression, schizophrenia or obsessive
compulsive disorder.
* * *
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Lower
animals are often seen as robotic and programmed in their actions and
reactions to the world. Insects, with their stiff little frames and
apathetic eyes, seem to epitomize such qualities.
But scientists studying fruit flies say they have discovered that the
little bugs have been slandered: they in fact display con siderable
spontaneity, which may be the evolution ary root of what we sense as
“free will.”
The research could help shed light on a centuries-old debate about what
free will is—and whether anyone really has it, or whether, instead, a
mindless movement of atoms in our brains ultimately controls all
decisions.
The study appears in the May 16 issue of the research journal PLoS One.
“Animals and especially insects are usually seen as complex robots
which only respond to external stimuli,” said senior author Björn
Brembs from the Free University Berlin. When scientists see animals
responding differently even to the same stimuli, they typically
“attribute this variability to random errors in a complex brain.”
Using a combination of automated behavior recording and mathematical
analyses, the team of researchers found that such variability cannot be
due to simple random events but is generated spontaneously and
non-randomly by the brain. These results caught computer scientist and
lead author Alexander Maye from the University of Hamburg, Germany by
surprise: “I would have never guessed that simple flies who otherwise
keep bouncing off the same window have the capacity for nonrandom
spontaneity if given the chance.” The researchers tethered fruit flies,
Drosophila melanogaster, in uniform white surroundings and recorded
their turning behavior. The flies in this setup receive no visual cues
from the environment and since they are fixed in space, their turning
attempts have no effect. Thus lacking any input, their behavior should
resemble random noise, similar to a radio tuned between stations, the
invest igators reasoned.
However, the analysis found that fly behavior is very different.
Various increasingly complex random computer models failed to
adequately account fly behavior, the researchers said.
They found the source of the spontaneity, they added, after analyzing
the behavior with methods developed by co-authors George Sugihara and
Chih-hao Hsieh from the Scripps Institution of Oceanography at the
University of California San Diego. “We found that there must be an
evolved function in the fly brain which leads to spontaneous variations
in fly behavior” Sugihara said. “The results of our analysis indicate a
mechanism which might be common to many other animals and could form
the biological foundation for what we experience as free will.” Our
subjective notion of “Free Will” is an oxymoron: the term ‘will’ would
not apply if our actions were completely random and it would not be
‘free’ if they were entirely determined, Brembs remarked. So if there
is free will, it must be somewhere between chance and necessity—just
where fly behavior lies. “The question of whether or not we have free
will appears to be posed the wrong way,” said Brembs. “Instead, if we
ask ‘how close to free will are we’ one finds that this is precisely
where humans and animals differ.” The next step will be to use genetics
to localize and understand the brain circuits responsible for the
spontaneous behavior, researchers added. This could lead to the
development of robots with the capacity for spontaneous nonrandom
behavior and may help combating disorders leading to compromised
spontaneous behavioral variability in humans such as depression,
schizophrenia or obsessive compulsive disorder.
|