From: Eugene Frison <cthulhu_calls.nul> Date: Sun, 22 Apr 2012 14:34:11 -0500 Archived: Mon, 23 Apr 2012 07:15:21 -0400 Subject: Re: Ufology And Psychiatry - Summary >From: David Rudiak <drudiak.nul> >To: post.nul >Date: Sat, 21 Apr 2012 15:52:00 -0700 >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 >><snip> >>>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 >>conclusion. >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 >solid. >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 >artificial. >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. This is all accurate and relevant important information, David. It is the meat and potatoes - the something we can sink our teeth into - that I requested from Cathy when she brought up vision researchers. The something other than 'things are this way' statements that she was making without example or reference to back them up. Nothing here damages my point in any way. I requested it from Cathy because she was apparently referring to it (without providing it, as you have) to support her contention that the premise that says human perception is reliable, is wrong. As you so eloquently point out in your remarks above, these vision research experiments are involving visual illusions that are not usually seen in the everyday world, and are stripped of vital clues usually present in the everyday world. So, while they may provide us with some information as to how vision works, they are not representing the real world and the situation we real human beings find ourselves in within it. So Cathy can't use this research to support her contention that the premise that says human perception is unreliable, is wrong. Had she provided the above information, I would have said this to her, rather than to you. As it turns out, in the everyday world, reality is much more complicated and different, and a lot of evidence from empirical experimentation in scientific fields other than psychology, as well as from everyday observation, are saying something different than what Cathy is saying. Now, as you said, a psychologist _might_ interpret the above- mentioned vision experiments to be producing results that are more examples of how unreliable human perception is. Considering the evidence that has come in from other sources, he or she just _might_ be right. This is a concept that Cathy and her supporters can't seem to wrap their minds around. Listen to 'Strange Days... Indeed' - The PodCast At: http://www.virtuallystrange.net/ufo/sdi/program/ These contents above are copyright of the author and UFO UpDates - Toronto. They may not be reproduced without the express permission of both parties and are intended for educational use only.
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