Ongoing eye movements constrain visual perception.

Eye movements markedly change the pattern of retinal stimulation. To maintain stable vision, the brain possesses a variety of mechanisms that compensate for the retinal consequences of eye movements. However, eye movements may also be important for resolving the ambiguities often posed by visual inputs, because motor commands contain additional spatial information that is necessarily absent from retinal signals. To test this possibility, we used a perceptually ambiguous stimulus composed of four line segments, consistent with a shape whose vertices were occluded. In a passive condition, subjects fixated a spot while the shape translated along a certain trajectory. In several active conditions, the spot, occluder and shape translated such that when subjects tracked the spot, they experienced the same retinal stimulus as during fixation. We found that eye movements significantly promoted perceptual coherence compared to fixation. These results indicate that eye movement information constrains the perceptual interpretation of visual inputs.