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Re: Ufology And Psychiatry - Summary

From: David Rudiak <drudiak.nul>
Date: Sat, 21 Apr 2012 15:52:00 -0700
Archived: Sun, 22 Apr 2012 08:30:26 -0400
Subject: Re: Ufology And Psychiatry - Summary

>From: Cathy Reason <Cathym.nul>
>To: UFO UpDates - Toronto <post.nul>
>Date: Sat, 21 Apr 2012 11:42:17 +0100
>Subject: Re: Ufology And Psychiatry - Summary

>>From: William Treurniet <wtreurniet.nul>
>>To: post.nul
>>Date: Thu, 19 Apr 2012 14:05:17 -0400
>>Subject: Re: Ufology And Psychiatry - Summary

>>The comment that the unreliability of human perception is an
>>assumption is demonstrably wrong given the oft-demonstrated
>>variability in relevant experimental data.

>We can see how this sort of circular reasoning operates in the
>case of visual illusions.

>To the vision researcher, these offer an opportunity to examine
>the mechanisms by which the brain extracts information from the
>visual world. By constructing experimental artifacts, one can
>test hypotheses based on how the visual system behaves in highly
>novel and constrained situations.

>Psychologists on the other hand proceed from the premise that
>all human perception is unreliable. The purpose of all
>experiments is then to provide an ever-lengthening list of
>examples of unreliable perception. It matters not that these
>examples are largely artifacts - the premise dictates the

Dead on Cathy! Visual illusions are actually quite rare in a
natural environment, otherwise we would be suffering from them
all the time. Most illusions you see in a book on human
perception are the result of highly artificial situations that
one usually would not encounter in normal life, usually a very
simplified, geometric drawing with all sorts of normal cues
stripped out that would have prevented the illusion from arising
in the first place.

One such example is spoke-like lines radiating out of a central
point, with two straight parallel lines drawn through them. The
two lines appear to be arced instead of straight. Interestingly,
the illusion can be somewhat suppressed by interpreting the
spokes as receding into the distance toward the vanishing point.

To a vision researcher, this tells us something about the
processing of straight lines in the brain (also a little about
depth perception). E.g., one explanation is that neurons
responding to different orientations of lines inhibit one
another in the brain, resulting in acute angles appearing a
little larger than they geometrically are and obtuse angles a
little smaller. If you apply that to the above illusory drawing,
the local small distortions of angles will cause the straight
lines to arc a little bit when the brain interprets the overall
shape of the lines.

But in a normal situation, the mechanism helps the brain
distinguish orientations of edges and sharpens up differences.

In computer image processing, it is well known that filters
applied to a scene can help bring out certain features, but at
the expense of creating artifacts. The brain is no different.
Evolution has led to the brain applying various neural filters
to the image that assist us in representing the scene and
ultimately interpreting it. These sometimes create illusions,
but usually one has to work pretty hard to mislead the
perceptual system.

Interpretation, which is an end-product of raw perception, can
also be faulty, but there is nothing inherently true in an
image, which can have multiple ambiguous interpretations, also
raw fodder for generating illusions for those perceptual
studies. E.g., an old classic illusion is the Necker cube,
nothing more than a black and white line drawing of a cube with
"front" and "back" faces the same size. What is "front" and what
is "back" is ambiguous and can and will flip back and forth. And
you can, of course, not interpret it as a 3D cube, but as a flat
line drawing of two squares connected by slanted diagonals, or
just a bunch of intersecting lines. There really is no inherent
"cube" there. We tend to prefer to interpret the drawing as a

A real 3D cube, particularly one made only of edges and not
solid, can also be mentally flipped, but this is more difficult,
and that can result in more illusions. The front and back
surfaces are no longer the same size, also in different focal
planes. Note that in normal viewing with two eyes, the following
illusions will usually not arise, because our binocular vision
and depth perception will prevent the illusions from arising in
the first place, again our perceptual system usually being quite
accurate and robust. It is usually only in an artificial
laboratory setting with multiple cues stripped out that the
illusions will arise. Thus, subjects need to view the scene with
one eye, not two.

In the normal situation, it looks like a proper cube with
everything focused right, but when you mentally flip it in
becomes a trapezoidal solid, where the focus of the front and
back also do not appear to be consistent. Thus already there is
an additional cue that something is not quite right. More
inconsistencies arise when you rotate the solid in your hand. As
a cube, it rotates consistent with another part of your brain's
understanding of what direction you are rotating it in, but
reversed it appears to paradoxically rotate in the opposite
direction. This illustrates how the visual brain areas are
communicating with one another to keep the visual interpretation
consistent, but this conflicts with the sensory and motor ones.
Again, we quickly smell a rat that something is not right with
how we are seeing things.

Another striking illusion with a rotating wire cube is putting a
straight stick through it. Viewed as a normal rotating cube, the
stick remains in rigid relationship to the cube, following the
rotation of the cube and we properly see it as a straight stick
going through two surfaces. But when the brain mentally flips
the depth and it becomes the reverse-rotating trapezoidal solid,
the stick no longer remains straight but seems to rapidly
contort into all sorts of extreme shapes. This is again the
visual brain trying to keep all elements consistent with one
another. The stick shape has to morph and seem to twist to
maintain its proper geometric relationship with the illusory
trapezoidal solid. But again, the situation is pretty

To the vision researcher, this is another example of how the
various visual brain interpretation mechanisms work hand-in-hand
to maintain a consistent interpretation of the entire scene. But
a psychologist (or a debunker) might interpret this as another
example of how unreliable human perception is.

For fun, you can also try to flip a solid cube, like your
Rubik's cube, and other interesting illusions arise, such as
surfaces that seem to have no depth and the colors now look like
stained glass illuminated from behind. To get it to work, you
have to concentrate a lot and stare a long time until your
nervous system begins to fatigue and the alternate, non-
fatigued, but less favorable interpretation can occur, again not
a normal situation.

David Rudiak

Listen to 'Strange Days... Indeed' - The PodCast



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