Rudolf Hooijenga wrote: >I have often noticed, while viewing an ordinary television set, that if >I turned my head sideways I could easily see the lines making up the >image, where while I watched the screen in the normal way, they did not >bother me at all.
>In other words, the same lines that do not show up when they run >horizontally, are easily visible when they run vertically. >Of course this is not quite the same problem, but possibly quite >related- perhaps to ones having two eyes spaced in the horizontal? ===================================================== Rudolf, My original "little experiments" had to do with estimation of the center of a geometrically defined figure where the finest descrimination required was deliberately made larger than the "normal" limit of resolution, so that in that sense it was a test of the judgement of symmetry, not one of perceiving small visual spacings, per se. The ability to make the estimate of the half-way division point was distinguishably better for horizontal judgements than for the vertical. (In total, I accumulated records of 30 trials each, from 62 volunteer subjects in that particular study, but have, over the years, made many related variations of the tests on smaller samples. Often, the only testee was myself!) It would be interesting to know the basis for the choices made in the arrangement of the television set's raster. So too, with our conventional system for writing, and subsequently printing. Certainly in these cases, the information is packed more densely horizontally than vertically. Question: Do persons with uncorrected astigmatism tend to preferentially accomodate for best horizontal, or for best vertical focus? Biologically, bilateral symmetry seems associated with locomotion. Radial symmetry is only common in sessile forms, or in slow-swimming aquatic animals that move fairly passively, at the mercy of water currents. Perhaps horizontally disposed paired eyes at the front end are a sign that it is adaptively about equally as important to turn right as it is to turn left. In terms of natural selection, dangers and opportunities tend in general to occur uniformly distributed in probable azimuth, but not so uniformly in elevation. Many creatures' lives are related to horizontal surfaces, and their attention tends to be deployed accordingly. Pet owners may have noticed that their dog is much more likely to see a thrown toy if it comes to rest at or near the ground, than if it lodges in a tree or shrub above the animal's eye level. Of course small prey species tend to have their long-range sense organs concentrated on their top surfaces, and their predators are often likely to approach from above them. Humans are opposite in being better suited to pay attention to the ground beneath their feet than to the sky above their heads. (Star-gazers get sore necks. But then, we are more likely to trip over a stone than over a star.) As seems to happen with sundial threads, we have wandered quite far afield in following this one. Bill.
