Connection/correspondence problem

1. This problem is most easily demonstrated with Ternus's apparent motion display.
As the two frames of this animation alternate, one perceives motion, but the nature of that motion depends on which disk in the first frame is connected with (put into correspondence with) which disk in the second frame. In one organization, we see a pair of discs shifting to the left and right, whereas in the other we see one disk remaining stationary in the middle while the second disk moves from the left to the right of the stationary disk. A similar problem arises with stereoscopic depth perception, where it must be determined which elements in the left eye's view of the world should be connected with which in the right. In static dot patterns, such as constellations in the night sky, there are multiple ways perceivers can see depending on which elements are seen as connected with which others. Thus, four dots arranged in an imaginary square could be perceived as a square, as an X, as a U, as two vertical lines one alongside the other, as two horizontal lines one above the other, and so forth. (JRP, February 1, 2007)