In the 1970s, Libet was researching neural activity and sensation
thresholds. His most famous and controversial experiment demonstrates
that unconscious electrical processes in the brain (the 'readiness
potential') precede conscious decisions to perform volitional,
spontaneous acts. The implication is that unconscious neuronal
processes precede and perhaps cause volitional acts. The subject
becomes aware of his or her intention to act, and retroactively
ascribes that intention to a (sometimes spurious) conscious
motivation. Most of the time, consciousness is trying to make
sense of changes to the body's state and the body's reflexive,
automatic responses after the fact, via formation of memories.
As Gerald Edelman puts it, consciousness is the 'remembered
present,' a constantly updated set of models of the body's
changing state.
Libet and his fellow researchers had each subject sit at
a desk in front of an oscilloscope timer. The subject carried
out some small, simple motor activity, like pressing a button
or flexing a finger or wrist, within a certain time frame.
Subjects noted the position of the dot on the oscilloscope
timer when he or she was first aware of the wish or urge to
act. Pressing the button also recorded the position of the
dot on the oscillator, this time electronically. By comparing
the marked time of the button's pushing and the subject's
conscious decision to act, researchers were able to calculate
the total time of the trial from the subject's initial volition
through to the resultant action. On average, approximately
two tenths of a second elapsed between the person's conscious
will to press the button and the act of pressing it.
When researchers analyzed EEG readings from each subject,
they discovered that brain activity involved in the initiation
of an action, primarily centered in the secondary motor cortex,
occurred around half a second before the subject pushed the
button. Libet and company were seeing mounting brain activity
preparing for the subject's button push as long as three tenths
of a seconds before the subjects reported their first awareness
of a conscious will to act.
If unconscious processes in the brain are the true initiator
of volitional acts, as Libet's experiments suggest, then what
does that mean for free will? If the brain has already taken
steps to initiate an action before we're aware of any desire
to perform it, doesn't that all but eliminate the causal role
of consciousness in volition? Libet himself finds room for
free will in the interpretation of his results, but only as
a kind of veto power. While consciousness plays no part in
the instigation of volitional acts, Libet sees its role as
suppressing or withholding from certain acts instigated by
the nonconscious. He notes that we have all experienced a
withholding from acting on a reflex or an urge. Since the
subjective experience of the conscious will to act preceded
the action by only two tenths of a second, this leaves consciousness
only 100-150 milliseconds to veto an action. In emergencies
or moments where consciousness has its limited bandwidth completely
occupied, free will goes right out the window.
People think of their consciousness as being in the 'driver's
seat' of the body, inhabiting it and animating it like a little
person piloting a giant robot. But if that's really true,
how does the little pilot's mind work? Is there another even
littler pilot inside? Consciousness isn't the body's boss,
it's a process of the body, like digestion and hormone production.
Your mind can work fast, but not instantaneously. Like all
other bodily processes, consciousness is a huge network of
interconnected thermodynamic interactions. All the efflorescence
and pruning of neural pathways takes time, and the more information
there is to process, the longer it takes.
Think of your consciousness as being less like the king,
and more like the entire US government, federal, state and
local included. It's an elaborate system of systems of systems
of agents, some of which work in concert, some of which are
at cross purposes, some of which are just shuffling paper
around because they're not sure what else to do. Like the
US government, there isn't a clear hierarchical structure.
Instead, consciousness more like a big mass of interest groups
and power centers, sometimes cooperating, sometimes competing.
Like the US government, consciousness can't make anything
happen without building consensus, and sometimes consensus
can't be achieved. Sometimes there are filibusters and shutdowns
and strikes. Sometimes there's even a violent coup d'etât.
To add to the confusion, the minds of modern people are host
to vast profusions of memes, the way our bodies are host to
billions of microbes. Think of all of your resident memes
as colonial governors who take an active role in your internal
affairs, exploiting them for benefit of their allies in the
global memepool. Does the entire US government, taken together,
have 'free will'? The president is as close as we come, but
even the president faces very tight constraints on his actions,
both real and perceived.
Should we be alarmed?
Susan Blackmore says we shouldn't. I concur.
© ethan hein 2007 | back
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