Binocular rivalry

When the images presented to the eyes differ only in their lightnesses, a form of rivalry called binocular lustre may be seen.

He reported that he could read from one book at a time and that changing from one to the other required withdrawing the "visual virtue" from one eye and moving it to the other.

Wheatstone also discovered binocular stereopsis, the perception of depth arising from the lateral placement of the eyes.

Wheatstone was able to prove that stereopsis depended on the different horizontal positions (the horizontal disparity) of points in the images viewed by each eye by creating the illusion of depth from flat depictions of such images displayed in his stereoscope.

Although Wheatstone's discovery of stereopsis supported fusion theory, he still had to account for binocular rivalry.

He regarded binocular rivalry as a special case in which fusion is impossible, saying "the mind is inattentive to impressions made on one retina when it cannot combine the impressions on the two retinae together so as to occasion a perception resembling that of some external object" (p. 264).

Dutour speculated that the alternations could be controlled by attention, a theory promoted in the nineteenth century by Hermann von Helmholtz.

This theory was promoted in the nineteenth century by Helmholtz's traditional rival, Ewald Hering.

[full citation needed] The most comprehensive early study of binocular rivalry was conducted by B.

Moreover, when he asked his observers to refrain from moving their eyes over the attended stimulus, control was abolished.

Auditory and olfactory forms of perceptual rivalry can occur when there are conflicting and so rivaling inputs into the two ears[7] or two nostrils.