Monday Oct. 5, 2009
9:15 AM - 10:15 am
Your conscious experience is
not a function of the world, it is a function of the
neural networks of your brain. Therefore, the biology of
the brain and consciousness is as fundamental to
understanding the universe, as we know it, as the
high-energy physics of subatomic particles. This is
especially true for the study of sensory and cognitive
illusions, since they represent effects that clearly
stand out as not representing the real world. That is,
since illusions don’t match reality we can know that by
studying illusions we are studying exactly what the
brain is actually doing, and not just what we think the
brain should be doing. Your brain does a staggering
amount of pragmatic self-dealing guesswork and outright
confabulation in order to construct
the highly imperfect mental simulation of reality known
as “consciousness.” This is not to say that objective
reality isn’t “out there” in a very real sense – but no
one lives there. No one’s ever even been there for a
visit. Ironically, the fact that consciousness feels
like a solid, robust, fact-rich transcript of reality is
just one of the countless illusions your brain creates
for itself.
Illusions are not errors of the
brain. Far from it. Illusions arise from processes that
are critical to our survival. Our brains have developed
illusory processes so that we may experience the world
in a ready-to-consume manner. Remove the machinery of
illusion, and you unwind the entire tapestry of human
awareness. Illusions are those perceptual experiences
that do not match the physical reality. They are
therefore exquisite tools with which to analyze the
neural correlates of human perception and consciousness.
Neuroscientists have long known that they can only be
sure of where they stand, in terms of correlating neural
responses to awareness, when they correlate the
awareness of an illusion to the brain's response,
specifically because of the illusions' mismatch with
reality. The study of illusions is therefore of critical
importance to the understanding of the basic mechanisms
of sensory perception and conscious awareness.
If you’ve ever seen a good magician perform, you know
how thrilling it is to watch the impossible happening
before your eyes. The laws of physics, probability,
psychology and common sense – the four trusty compass
points in your mental map of reality – are suddenly
turned into liabilities. Objects and people appear,
vanish, levitate, transpose, transform, and with all
your smarts you can’t imagine how it’s being done.
Magicians are the premier artists of attention and
awareness, and they manipulate our cognition like clay
on a potter's wheel.
And the mechanisms
underlying magic perception have implications for our
daily lives. The magical arts work because humans have
hardwired processes of attention and awareness that are
hackable. By understanding how magicians hack our
brains, we can better understand how we work. |
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Stephen L. Macknik
Barrow
Neurological Institute
Susana Martinez-Conde
Barrow Neurological
Institute |
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Stephen and Susana
are laboratory directors at the Barrow
Neurological Institute (BNI) in Phoenix,
Arizona, where they study various aspects of
visual, sensory and cognitive neuroscience.
Their research and outreach activities have been
written up in hundreds of media stories
including many that have appeared in The New
York Times, The Wall Street Journal, The Chicago
Tribune, The Boston Globe, National Public
Radio, Der Spiegel, New Scientist and Wired
magazine. Both are monthly columnists for
ScientificAmerican.com. Their shared column on
the neuroscience of illusions gets hundreds of
thousands of hits every month. One of their
recent column contributions is the most
downloaded article in sciam.com history.
Stephen
and Susana are founding board members
of the Neural Correlate Society, and
Susana serves as its Executive Chair.
NCS hosts the annual “Best Visual
Illusion of the Year Contest.” The
contest’s website maintains an archive
of visual illusions and their
explanations for a broad audience, and
receives almost three million hits per
year. They both serve on the board of
advisors for Scientific American: Mind
and in addition to their column have
published several feature articles in
Scientific American (circulation >
1,000,000 readers) and several of its
family of journals. Their academic
publication credits include
contributions to Nature, Nature
Neuroscience, Neuron, Nature Reviews
Neuroscience, and the Proceedings of
the National Academy of Science, and
they have each authored over 50
academic publications.
Stephen
is Director of the Laboratory of
Behavioral Neurophysiology at BNI. He
received a B.A. in Psychobiology,
Psychology, and Biology from the
University of California, Santa Cruz,
and a Ph.D in Neurobiology at Harvard
University. He was a postdoctoral
fellow with the Nobel Laureate Prof.
David Hubel at Harvard Medical School,
and also with Prof. Zach Mainen at
Cold Spring Harbor Lab. He led his
first independent laboratory at
University College London before coming
to BNI in 2004.
Susana is Director of the Laboratory of Visual
Neuroscience at BNI. She received a
B.S. in Experimental Psychology from
Universidad Complutense de Madrid and
a Ph.D in Medicine and Surgery from
the Universidade de Santiago de
Compostela. She was a postdoctoral
fellow with Nobel Laureate David Hubel
at Harvard Medical School, and then an
Instructor in Neurobiology at the same
institution. She was a Lecturer at
University College London from 2001 to
2003 before assuming her directorship
at BNI the following year. |
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