Binocular rivalry and reciprocal inhibition

Any explanation of binocular rivalry based on a reciprocal inhibition mechanism would require that unilateral increases in the stimulus strength of the rivalry target in one eye produce increases in the mean nonsuppression duration of that eye and concommitant decreases in the mean nonsuppression duration of the contralateral eye. To test that hypothesis, the stimulus strength (in this case, contrast) of one rivalry target was varied (0.1, 1, 10, and 100 ft-L) while the strength of the target in the other eye remained constant. The data, obtained from six experienced Ss, indicate that variations in stimulus strength do not alter the mean nonsuppression duration of the recipient eye. This outcome offers a fundamental difficulty for the reciprocal inhibition concept. A model that assumes partially independent suppression and dominance mechanisms is suggested as a more adequate alternative.