Abstract
Background. When conflicting images are shown continuously to the two eyes, observers perceive either image in turn; perception fluctuates. When conflicting images are periodically turned off and back on, observers tend to perceive the same image on many consecutive presentations; perception stabilizes. This stabilization seems to reveal a priming trace of past dominance that acts during the current presentation, biasing perceptual competition in favor of the previously dominant pattern. This trace accumulates over presentations, so that a pattern that has dominated several times is more likely to regain dominance than a pattern that has dominated only once. Given this plausible account of percept repetition, why does perception switch at all during intermittent rivalry?
Methods. We presented rival stimuli intermittently and determined the frequency at which perception switched. In additional experiments we varied the blank duration that separates presentations; a parameter known to affect switch probability.
Results and Conclusion. Switches, although infrequent, were highly periodic, ruling out random fluctuations as their cause. Oscillation periods were on the order of minutes (hundreds of presentations), indicating that switches involve a signal that accumulates over minutes. Strikingly, the relation between blank duration and switching probability varied systematically with position within a slow oscillation cycle. These findings can be accommodated by a revised version of an existing model of perceptual stabilization1. Based on these results, knowledge of an observer's percept history can be used to predict future perception. Furthermore, the systematic evolution of the relation between blank duration and switch probability allows control over future perception by online adjustment of the blank duration.
NIH-EY13358.
1. Noest A. J., van Ee R., Nijs M. M., van Wezel R. J. (2007). Journal of Vision 7(8): 10, 1-14.