Just in case you really trust your senses, along comes this. The
warning here though is that several forms of distractions will cause
your brain to serious errors. Thus briefly observed phenomena are
rather dangerous which we knew. Yet the interruption needs to be
brief to properly realize the effect and the observer quite unaware
also. A questioning mind will want confirmation which eliminates the
confusion.
Whenever is see a report of a bizarre event, I want to see plenty of
time. Yesterday I reported on a remarkable UFO sighting in which the
observer had five full minutes to inspect a complex tableau. That
becomes pretty solid. She had time to form questions and make
conclusions. Her coworkers were limited to a quick image of the
craft retreating and are consistent with the majority of such
stories.
This reminds me that in order to see, the mind must be prepared. If
a strange artifact confounds, it disappears into storage. In this
way 10,000 Minoan artifacts from the European Bronze Age located from
the copper mines of Lake Superior remain in storage since the 1920's
while scholars claim a lack of evidence.
Even more confounding evidence is out there.
The Science of
Illusion
By ALEX STONE
Published: June 22,
2012
PINCH a coin at its
edge between the thumb and first fingers of your right hand and begin
to place it in your left palm, without letting go. Begin to close the
fingers of the left hand. The instant the coin is out of sight,
extend the last three digits of your right hand and secretly retract
the coin. Make a fist with your left — as if holding the coin —
as your right hand palms the coin and drops to the side.
You’ve just
performed what magicians call a retention vanish: a false transfer
that exploits a lag in the brain’s perception of motion, called
persistence of vision. When done right, the spectator will
actually see the coin in the left palm for a split second after the
hands separate.
This bizarre
afterimage results from the fact that visual neurons don’t stop
firing once a given stimulus (here, the coin) is no longer present.
As a result, our perception of reality lags behind reality by
about one one-hundredth of a second.
Magicians have long
used such cognitive biases to their advantage, and in recent years
scientists have been following in their footsteps, borrowing
techniques from the conjurer’s playbook in an effort not to mystify
people but to study them. Magic may seem an unlikely tool, but it’s
already yielded several widely cited results. Consider the work on
choice blindness — people’s lack of awareness when evaluating the
results of their decisions.
In one study, shoppers
in a blind taste test of two types of jam were asked to choose the
one they preferred. They were then given a second taste from the jar
they picked. Unbeknown to them, the researchers swapped the flavors
before the second spoonful. The containers were two-way jars, lidded
at both ends and rigged with a secret compartment that held the other
jam on the opposite side — a principle that’s been used to bisect
countless showgirls. This seems like the sort of thing that wouldn’t
scan, yet most people failed to notice that they were tasting the
wrong jam, even when the two flavors were fairly dissimilar, like
grapefruit and cinnamon-apple.
In a related
experiment, volunteers were shown a pair of female faces and asked
which they found more attractive. Then they were given a closer look
at their putative selection. In fact, the researchers swapped the
selection for the “less attractive” face. Again, this bit of
fraud flew by most people. Not only that, when pressed to justify
their choices, the duped victims concocted remarkably detailed
post hoc justifications.
Such tricks suggest
that we are often blind to the results of our own decisions. Once
a choice is made, our minds tend to rewrite history in a way that
flatters our volition, a fact magicians have exploited for centuries.
“If you are given a choice, you believe you have acted freely,”
said Teller, of the duo Penn and Teller, to Smithsonian
magazine. “This is one of the darkest of all psychological
secrets.”
Another dark
psychological secret magicians routinely take advantage of is
known as change blindness — the failure to detect changes in
consecutive scenes. One of the most beautiful demonstrations is an
experiment conducted by the psychologist Daniel Simons in
which he had an experimenter stop random strangers on the street and
ask for directions.
Midway through the
conversation, a pair of confederates walked between them and blocked
the stranger’s view, and the experimenter switched places with one
of the stooges. Moments later, the stranger was talking to a
completely different person — yet strange as it may sound, most
didn’t notice.
What are the neural
correlates of these cognitive hiccups? One possible answer comes from
studies of the so-called face test, in which a volunteer is shown two
faces in quick succession. Normally, just about anyone can
distinguish the faces provided they’re shown within about half a
second. But if the person is distracted by a task like counting, or
by a flashing light, the faces start to look the same.
Here’s where it gets
interesting, though. Scientists have found a way to induce change
blindness, with a machine called a transcranial magnetic stimulator,
which uses amagnetic field to disrupt localized brain regions.
In one experiment, a T.M.S. was used to scramble the parietal cortex,
which controls attention. Subjects were then given the face test.
With the machine turned off, they did fine. But when the T.M.S. was
on, most failed the test. Conclusion? Misdirection paralyzes part of
your cortex.
Such blind spots
confirm what many philosophers have long suspected: reality and our
perception of it are incommensurate to a far greater degree than is
often believed. For all its apparent fidelity, the movie in our heads
is a “Rashomon” narrative pieced together from inconsistent and
unreliable bits of information. It is, to a certain extent, an
illusion.
Alex Stone is the
author of “Fooling Houdini: Magicians, Mentalists, Math Geeks and
the Hidden Powers of the Mind.”
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