Normally Scientific
American has some fairly intelligent articles, although it
occasionally gives us goofy drivel that insults the intelligence of
anyone who managed to progress beyond elementary school. An example
is a recent article entitled “What Neuroscience Says About Free
Will.”
The author suggests an
absurd hypothesis: “Perhaps in the very moments that we experience
a choice, our minds are rewriting history, fooling us into thinking
that this choice—that was actually completed after its consequences
were subconsciously perceived—was a choice that we had made all
along.” Subconscious “rewriting history” in just a moment of
time? Get real.
The author then describes
an experiment he did apparently designed to support this idea. The
experiment is described as follows:
Participants were
repeatedly presented with five white circles in random locations on a
computer monitor and were asked to quickly choose one of the circles
in their head before one lit up red. If a circle turned red so fast
that they didn’t feel like they were able to complete their choice,
participants could indicate that they ran out of time. Otherwise,
they indicated whether they had chosen the red circle (before it
turned red) or had chosen a different circle. Unbeknownst to
participants, the circle that lit up red on each trial of the
experiment was selected completely randomly by our computer script.
Hence, if participants were truly completing their choices when they
claimed to be completing them—before one of the circles turned
red—they should have chosen the red circle on approximately 1 in 5
trials. Yet participants’ reported performance deviated
unrealistically far from this 20% probability, exceeding 30% when a
circle turned red especially quickly.
The author suggests
absurdly that this little test suggests something
about free will – that “it might be nothing more than a trick the
brain plays on itself.” The experiment suggests nothing at all
about free will. The experiment simply tells us minor stuff about
human performance and memory that we already knew.
Here are some basic facts
about human performance and memory that are rather well known:
- When they don't have much motivation, people may perform poorly on tests that require concentration.
- People may perform poorly on boring tests.
- People may perform poorly on tests that ask them to do something they have never tried to do.
- People remember fairly well interesting or important things (such as a human face), but may have a poor remembrance of abstract things such as the position of white circles on a computer screen.
- People have a good memory for important choices, but don't remember well meaningless choices such as which of 5 white circles on a computer screen they chose in their minds.
- Performance tends to deteriorate when things are sped up so that things are appearing on the test screen “especially quickly.”
The fact that performance
tends to degrade unpredictably when humans interface with a machine
that is sped up “especially quickly” has been known since as
least the 1950's, when it was demonstrated in this hilarious scene
from the “I Love Lucy” television show starring Lucille Ball.
Given all these things, it
is predictable that you would get exactly the results reported, even
if free will is perfectly real, and even if there is nothing at all
like “the mind tricking itself.”
Now given these facts,
imagine you are some college student who has signed up for some test
like the test described. You know that no matter how poorly you
perform, you will get the same reward (which may be an hourly wage
or perhaps some academic credit). So when the test speeds up, are
you going to concentrate very hard, trying real hard to remember
where those boring little white circles were on the screen? Knowing
that it makes no difference whether you try hard, you will be just as
likely to not try very hard (perhaps while the test is running,
you'll be daydreaming or thinking about that pretty woman you saw
last night). So when you see some little red circles popping up at
a faster rate, there's a good chance that you'll just kind of “flip
a coin” in your mind as to whether or not you specify that was the
position that you previously chose in your mind. Knowing that the
experimenter can't know which white circle you chose in your mind,
you may be thinking to yourself, “No one will ever know.” Given
a certain fraction of slacker subjects who are just lazily taking
this kind of approach to the test, we would expect exactly the
results reported.
Even if we imagine no such
slacker subjects, the results reported could be plausibly explained
by simply imagining that humans don't do very well at remembering
meaningless choices they have made, and don't remember well the
positions of meaningless things. In fact, we're not even very good at
remembering the position of meaningful things. If you ask someone to
bring up an image of Brad Pitt, and then close the image, and then
ask that person on which fourth of the computer screen Brad's head
was located, there is maybe a 25% chance they'll give the wrong
answer. The fact that there was an option in the test for specifying
“I didn't have time to choose” means very little, because
subjects would have a psychological aversion for selecting an option
which might tend to identify them as slow-minded (a kind “I'm a
slow dummy” button).
The author's laughable
suggestion that the predictable result of the experiment is an
example of neuroscience telling us something about free will (that
free will is an illusion) is just an example of pretentious glory
hunger. Entirely lacking in such grandiose implications, the trivial
experiment is so unsurprising that it deserves nothing but a yawn.
The experiment is also not an example of neuroscience, which the
Merriam Webster dictionary tells us is “ a branch (as
neurophysiology) of the life sciences that deals with the anatomy,
physiology, biochemistry, or molecular biology of nerves and nervous
tissue and especially with their relation to behavior and learning.”
Doing little experiments like this (without monitoring of the brain)
is not neuroscience, but mere garden-variety psychology
experimentation. Psychology experimentation is soft science, and it
should not be sold as hard science.
The lesson we can learn
here is that we should not assume scientists are always reliable
interpreters of the data they collect. They very often are not. Given
a choice between interpreting some data in a plausible way, and
between interpreting the data in some implausible way that matches
his philosophical biases, a scientist may choose the latter.
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