[tt] NYT: Mirrors Used to Explore How the Brain Interprets Information

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Mirrors Used to Explore How the Brain Interprets Information
http://www.nytimes.com/2008/07/22/science/22angi.html

Basics
By NATALIE ANGIER

For the bubbleheaded young Narcissus of myth, the mirror spun a
fatal fantasy, and the beautiful boy chose to die by the side of a
reflecting pond rather than leave his "beloved" behind. For the
aging narcissist of Shakespeare's 62nd sonnet, the mirror delivered
a much-needed whack to his vanity, the sight of a face "beated and
chopp'd with tann'd antiquity" underscoring the limits of self-love.

Whether made of highly polished metal or of glass with a coating of
metal on the back, mirrors have fascinated people for millennia:
ancient Egyptians were often depicted holding hand mirrors. With
their capacity to reflect back nearly all incident light upon them
and so recapitulate the scene they face, mirrors are like pieces of
dreams, their images hyper-real and profoundly fake. Mirrors reveal
truths you may not want to see. Give them a little smoke and a house
to call their own, and mirrors will tell you nothing but lies.

To scientists, the simultaneous simplicity and complexity of mirrors
make them powerful tools for exploring questions about perception
and cognition in humans and other neuronally gifted species, and how
the brain interprets and acts upon the great tides of sensory
information from the external world. They are using mirrors to study
how the brain decides what is self and what is other, how it judges
distances and trajectories of objects, and how it reconstructs the
richly three-dimensional quality of the outside world from what is
essentially a two-dimensional snapshot taken by the retina's flat
sheet of receptor cells. They are applying mirrors in medicine, to
create reflected images of patients' limbs or other body parts and
thus trick the brain into healing itself. Mirror therapy has been
successful in treating disorders like phantom limb syndrome, chronic
pain and post-stroke paralysis.

"In a sense, mirrors are the best `virtual reality' system that we
can build," said Marco Bertamini of the University of Liverpool.
"The object `inside' the mirror is virtual, but as far as our eyes
are concerned it exists as much as any other object." Dr. Bertamini
and his colleagues have also studied what people believe about the
nature of mirrors and mirror images, and have found nearly
everybody, even students of physics and math, to be shockingly off
the mark.

Other researchers have determined that mirrors can subtly affect
human behavior, often in surprisingly positive ways. Subjects tested
in a room with a mirror have been found to work harder, to be more
helpful and to be less inclined to cheat, compared with control
groups performing the same exercises in nonmirrored settings.
Reporting in the Journal of Personality and Social Psychology, C.
Neil Macrae, Galen V. Bodenhausen and Alan B. Milne found that
people in a room with a mirror were comparatively less likely to
judge others based on social stereotypes about, for example, sex,
race or religion.

"When people are made to be self-aware, they are likelier to stop
and think about what they are doing," Dr. Bodenhausen said. "A
byproduct of that awareness may be a shift away from acting on
autopilot toward more desirable ways of behaving." Physical
self-reflection, in other words, encourages philosophical
self-reflection, a crash course in the Socratic notion that you
cannot know or appreciate others until you know yourself.

The mirror technique does not always keep knees from jerking. When
it comes to socially acceptable forms of stereotyping, said Dr.
Bodenhausen, like branding all politicians liars or all lawyers
crooks, the presence of a mirror may end up augmenting rather than
curbing the willingness to pigeonhole.

The link between self-awareness and elaborate sociality may help
explain why the few nonhuman species that have been found to
recognize themselves in a mirror are those with sophisticated social
lives. Our gregarious great ape cousins -- chimpanzees, bonobos,
orangutans and gorillas -- along with dolphins and Asian elephants,
have passed the famed mirror self-recognition test, which means they
will, when given a mirror, scrutinize marks that had been applied to
their faces or bodies. The animals also will check up on personal
hygiene, inspecting their mouths, nostrils and genitals.

Yet not all members of a certifiably self-reflective species will
pass the mirror test. Tellingly, said Diana Reiss, a professor of
psychology at Hunter College who has studied mirror self-recognition
in elephants and dolphins, "animals raised in isolation do not seem
to show mirror self-recognition."

For that matter, humans do not necessarily see the face in the
mirror either. In a report titled "Mirror, Mirror on the Wall:
Enhancement in Self-Recognition," which appears online in The
Personality and Social Psychology Bulletin, Nicholas Epley and Erin
Whitchurch described experiments in which people were asked to
identify pictures of themselves amid a lineup of distracter faces.
Participants identified their personal portraits significantly
quicker when their faces were computer enhanced to be 20 percent
more attractive. They were also likelier, when presented with images
of themselves made prettier, homelier or left untouched, to call the
enhanced image their genuine, unairbrushed face. Such internalized
photoshoppery is not simply the result of an all-purpose preference
for prettiness: when asked to identify images of strangers in
subsequent rounds of testing, participants were best at spotting the
unenhanced faces.

How can we be so self-delusional when the truth stares back at us?
"Although we do indeed see ourselves in the mirror every day, we
don't look exactly the same every time," explained Dr. Epley, a
professor of behavioral science at the University of Chicago
Graduate School of Business. There is the scruffy-morning you, the
assembled-for-work you, the dressed-for-an-elegant-dinner you.
"Which image is you?" he said. "Our research shows that people, on
average, resolve that ambiguity in their favor, forming a
representation of their image that is more attractive than they
actually are."

When we look in the mirror, our relative beauty is not the only
thing we misjudge. In a series of studies, Dr. Bertamini and his
colleagues have interviewed scores of people about what they think
the mirror shows them. They have asked questions like, Imagine you
are standing in front of a bathroom mirror; how big do you think the
image of your face is on the surface? And what would happen to the
size of that image if you were to step steadily backward, away from
the glass?

People overwhelmingly give the same answers. To the first question
they say, well, the outline of my face on the mirror would be pretty
much the size of my face. As for the second question, that's
obvious: if I move away from the mirror, the size of my image will
shrink with each step.

Both answers, it turns out, are wrong. Outline your face on a
mirror, and you will find it to be exactly half the size of your
real face. Step back as much as you please, and the size of that
outlined oval will not change: it will remain half the size of your
face (or half the size of whatever part of your body you are looking
at), even as the background scene reflected in the mirror steadily
changes. Importantly, this half-size rule does not apply to the
image of someone else moving about the room. If you sit still by the
mirror, and a friend approaches or moves away, the size of the
person's image in the mirror will grow or shrink as our innate sense
says it should.

What is it about our reflected self that it plays by such
counterintuitive rules? The important point is that no matter how
close or far we are from the looking glass, the mirror is always
halfway between our physical selves and our projected selves in the
virtual world inside the mirror, and so the captured image in the
mirror is half our true size.

Rebecca Lawson, who collaborates with Dr. Bertamini at the
University of Liverpool, suggests imagining that you had an
identical twin, that you were both six feet tall and that you were
standing in a room with a movable partition between you. How tall
would a window in the partition have to be to allow you to see all
six feet of your twin?

The window needs to allow light from the top of your twin's head and
from the bottom of your twin's feet to reach you, Dr. Lawson said.
These two light sources start six feet apart and converge at your
eye. If the partition is close to your twin, the upper and lower
light points have just begun to converge, so the opening has to be
nearly six feet tall to allow you a full-body view. If the partition
is close to you, the light has nearly finished converging, so the
window can be quite small. If the partition were halfway between you
and your twin, the aperture would have to be -- three feet tall.
Optically, a mirror is similar, Dr. Lawson said, "except that
instead of lighting coming from your twin directly through a window,
you see yourself in the mirror with light from your head and your
feet being reflected off the mirror into your eye."

This is one partition whose position we cannot change. When we gaze
into a mirror, we are all of us Narcissus, tethered eternally to our
doppelgänger on the other side.