Distortions of Posterior Visual Space

Abstract

The study of spatial vision is a long and well traveled road (which, of course, converges to a vanishing point at the horizon). Its various distortions have been widely investigated empirically, and most concentrate, pragmatically, on the space anterior to the observer. The visual world behind the observer has received relatively less attention and it is this perspective the current experiments address. Our results show systematic perceptual distortions in the posterior visual world when viewed statically. Under static viewing conditions, observer's perceptual representation was consistently 'spread' in a hyperbolic fashion. Directions to distant, peripheral locations were consistently overestimated by about 11 degrees from the ground truth and this variability increased as the target was moved toward the center of the observer's back. The perceptual representation of posterior visual space is, no doubt, secondary to the more immediate needs of the anterior visual world. Still, it is important in some domains including certain sports, such as rowing, and in vehicular navigation.

Magic Circle

“…Why the difficulties? We speculate that this has to do with the fact that there is no visual space behind one’s back ( Phillips & Voshell, 2009 ). As a consequence, pictures are intuitively understood to only show part of what could be in front of one.…”

“…Naïve observers have considerable problems to deal with very wide-angle (but less than 180°) images ( Attneave & Farrar, 1977 ; Koenderink, van Doorn, de Ridder, & Oomes, 2010 ; Phillips & Voshell, 2009 ).…”

Vision, an Optical User Interface

“…Nobody feels there is anything behind their backs (Phillips & Voshell, 2009), no matter the size of their visual field. The 0° and the 360° people behave very similarly.…”

“…Suppose someone points at a person behind you, perhaps meant as a warning. Then, in your awareness, the former person points at you , because in your awareness there is nothing behind your back (Phillips & Voshell, 2009).…”

View From Outside the Viewing Sphere

“…For instance, observers estimate the extent of their visual fields ( Koenderink, van Doorn, & Todd, 2009 ) as being much smaller than it is (common), or much larger than it is (less common, but not infrequent). For most observers, the space behind their backs does not exist ( Attneave & Farrar, 1977 ; Phillips & Voshell, 2009 ). One takes an optic hemisphere for all there (optically) is.…”