Periodicity of strength of pattern in binocular rivalry.

The effect of suppression in binocular rivalry is divided into the effects of boundary and of region. By removing the effect of boundary from the double effects, we examined whether the strength of pattern oscillates throughout duration of suppression phase. Probabilities of appearance of the suppressed test patterns were measured immediately after the removal of the suppressing pattern at various temporal points after onset of suppression. The probabilities decrease, reach a minimum level, and then increase throughout the course of the suppression phase. Immediately after the beginning of the suppression phase, the small test pattern whose duration of suppression is short rarely appears, while the large pattern whose duration of suppression is long certainly appears. These results support our hypothesis for which the key assumption is that the strength of pattern periodically oscillates as a function of duration of observation time.