Binocular rivalry
Also called Binocular contour rivalry
Discovered by Porta in 1593 (Wade 1996). The essence is the interplay of perception with vision when you separate the visual stimuli of each eye. Each eye is presented with a separate image with a partition separating the effective visual field. A continuous cycle of the two images being recognizable (each in its own turn) with brief periods of mixed forms appearing. The belief is this effect may shed light onto the base mechanisms of perception.