Responsible
Thinking:
Principles
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Suggestion and Perception
A long time ago, at a lake cabin in New Hampshire, a friend of my parents
(call him John) was talking to his daughter's boyfriend about beer. The
boyfriend couldn't understand why John would drink Carling beer when
Schaefer was obviously superior. John poured beer into two glasses while
the boyfriend wasn't looking and asked him if he could tell which one was
which. The boyfriend tried them both and clearly expressed his preference
for the one he assumed was Schaefer. It turns out both were the same beer
(I don't recall
which one). Something peculiar was happening here. It seems that the
boyfriend's perception of taste was influenced not just by taste, but by
his expectation that the two beers were different.
A few years ago we had some friends at our house to try tasting different
foods and drinks. One of them was vanilla ice cream. We had three brands:
Haagen-Dazs, Kemps (a moderately priced brand popular in Minnesota) and an
inexpensive store brand. Our guests weren't told which was which. Most
of them clearly preferred both the Kemps and the store brand to the
Haagen-Dazs. They were surprised since they had initially assumed that
the Haagen-Dazs was better since it is quite expensive, has a high cream
content, and has a top-notch reputation. Since most people try many
brands of ice cream over their lives, we are likely to assume that the
reputation of a "premium" ice cream like Haagen-Dazs is the result of it
actually tasting better. In fact it may be that there is an illusion of
tasting better caused by expectations. It turns out that in blind tests,
where expectations cannot influence the perceptions, the results are often
unexpected.
When we form a judgment about something we have experienced ourselves,
like how much we like a beer or ice cream, we naturally assume our
judgment is based entirely on our own perception. However if we have a
prior expectation based on what someone has told us or something we have
assumed, that expectation may have a strong influence on our opinion that
we don't recognize. This is sometimes called the "power of suggestion".
It can lead us to false beliefs because we think we have determined
something for ourselves when in fact we are just passing on a (possibly
erroneous) impression we got elsewhere.
A common situation where perception is distorted by expectations is when
people judge value on the basis of price. A friend told me a story of a
shopkeeper who had some knick-knacks that had been priced at two dollars.
Nobody bought them. On a whim he raised the price to five dollars. To
his surprise they sold out quickly. Apparently buyers assumed that the
higher price implied better quality. While it is certainly true that
higher priced items have the potential to have higher quality, it is also
possible that high prices are due to advertising costs, ingredients that
are costlier but no better, or simply increased mark-up.
A number of years ago the concept of "pyramid power" became popular.
It involved the belief that pyramid shaped structures somehow focused
power in a way that was beneficial to things inside them. One of the
claims was that razor blades would stay sharper if stored in a pyramid shaped container
between uses. People who tried this were quite confident that it worked,
but their
judgment was made with full knowledge of whether the blades they were
using had been stored in the pyramid. When testing was done without the
possibility of bias, the effect disappeared. While it is relatively
harmless if we make mistaken judgments about the taste of ice cream or
beer, the pyramid case can be troublesome because it could lead people
to mistakenly believe in a miraculous effect that would invalidate
important principles of science. If taken seriously, scientists could
waste a lot of time and money trying to develop a scientific theory
about an effect that did not exist.
This type of problem is well known in science as the "placebo" effect,
and it often makes doing scientific experiments considerably more difficult.
Imagine that a new pain killing drug is being tested. If the patients who
are given the drug are expecting it to benefit them, they are likely to
report a benefit even if the drug is ineffective. It may be that they
actually feel better just because they know they are getting some sort
of treatment, or it may be that, believing the drug to be effective,
they assume they would have felt worse without it. To prevent getting
erroneous results because of this effect, experiments are usually designed
so that patients do not know whether they are getting a real treatment
or a fake treatment (known as a placebo). If the fake treatment is just
as helpful as the real one, then it is likely that any benefit reported
from the real one is just caused by the placebo effect and not the drug.
A dramatic case of suggestion influencing perception occurs with a phenomenon
known as "facilitated communication" which involves children with autism.
Martin Gardner
(2001)provided the following description of how
it works (Gardner uses masculine pronouns for the child since most autistic
children are male):
An autistic child is seated at a typewriter or computer keyboard, or perhaps
just a sheet of paper with the keyboard drawn on it… A therapist, usually a
woman, is called the child's "facilitator." She asks the child a
question, then grasps his wrist, or elbow - usually the hand - while the child
extends his index finger and begins to type. The belief is that the child has
the ability to communicate intelligent thoughts by typing, but lacks the
muscular coordination needed for finding the right keys. The facilitator assists
him in locating the keys she is sure he intends to hit.
A wondrous miracle now seems to take place. Although the child has been
thought to be
mentally retarded, unable to read, write, or speak coherently, he types
out lucid, sophisticated messages that could only come from a normal
intelligent mind.
The children were apparently able to answer questions, identify pictures,
and tell about their feelings. Facilitated communication was adopted in
many treatment centers around the world and described in newspapers and
magazines including Readers Digest. Some people, however, recognized
serious problems with the method, such as the fact that the child often
was not looking at the keyboard when he chose the keys. Eventually some
tests were done where the child was asked a question using earphones so
the facilitator could not hear what was said, and sure enough, the answers
were unrelated to the questions. In another test the child was shown a
picture and the facilitator was shown a different picture but led to
believe it was the same one the child saw. The typing represented what
the facilitator saw rather than what the child saw. Clearly facilitated
communication did not really work to communicate the child's thoughts,
but instead communicated the facilitator's expectations.
How does this related to things like beer tasting and placebos? It is
widely agreed that the facilitators were sincere people who were not
deliberately faking the results. Their choice of keys was based on
their own expectations of what the child might want to say rather than
their actual perception of the child's movements. So, like people
tasting foods or taking placebos, their perceptions were misled by
their expectations.
The problem presented by facilitated communication was particularly
serious because some of the messages wrongly believed to have come
from the autistic children involved accusations of sexual abuse.
Dozens of men were arrested based on this fallacious "testimony",
and some spent jail time before it was recognized that the information
was totally invalid.
An interesting case of mistaken perception was described by Phil Klass,
an investigator of UFO claims:
At approximately 8:45 P.M. CST on the night of March 3, 1968,
three well educated adults, standing outside near Nashville, Tennessee,
saw what they later described as a giant, saucer-shaped, metallic craft
with many square-shaped windows illuminated from inside the craft, headed
out of the sourthwest toward the northeast. It passed overhead silently
at an altitude estimated at only one thousand feet.
The U.S. Air Force also received a UFO sighting report from six persons
living near Shoals, Indiana, some two hundred miles north of Nashville,
who said they had seen the same object, which was described as being
cigar shaped, with numerous square windows illuminated from inside, and
with a rocketlike exhaust emitted from the rear of the craft. (Klass,
1981)
It turns out this object was the reentry of a Russian rocket booster that
had been used to launch the Soviet Zond 4 spacecraft.
Why did people describe it as having an oblong or saucer shape, the windows as square,
and only a thousand feet up when it was actually high in the sky hundreds
of miles away?
Probably because human perception tries to match what is seen with known
objects. In this case, an airliner seen in the dark with lit windows
would have looked similar to the
row of bright rocket fragments, so they probably used this as a starting
point for their
judgments about the object. An airliner would be expected to have square
windows, and judgment of its distance would be based on the spacing of
the "windows"
from each other. Their minds would have filled in the details, and since
the whole sighting took place in the span of just a few seconds, there
was no opportunity for more thoughtful examination. The end result is
that reliable people, attempting to be perfectly honest, tell a false
story. This is a quite normal type of human error, and could happen to
any of us.
Normally when we are confident someone is honest and they tell us that
they have learned something through direct personal experience, we feel
it must be true. This applies even more so when we feel we ourselves
have learned something from our own experience. Hopefully the above
examples show that even though people are honest, sane, and perfectly
intelligent, they can still have experiences and perceptions that are
wrong. It is important to take this into account when we are trying
to determine what is true.
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