Abstract
We used an acoustical vibrotactile stimulus applied under the subjects chin to vibrate the eye and induce a perceptual illusion that involves the observation of flickering images. If we give a tiny vibration to our eye, our perception of the environment does not change, but images on a flickering display may become illusory. Here we investigate this phenomenon using two main experiments, one using a controlled acoustical vibration, and the another changing the distance between subjects and the flickering image. The results of these experiments are used to develop a theoretical model in the attempt to rigorously explain the phenomenon. In the first experiment a controlled vibration in the acoustical range is transferred to the subject by a wooden stick placed horizontally under the chin. While manipulating the frequency, we asked the subjects to report the onset of the illusion and evaluate it in four levels of intensity. We found a Gaussian dependence between frequency and intensity, with center placed near the flickering frequency. In a second experiment with distance, we proved that this visual effect tends to be more prominent when far away and that it decays in proximity of the screen. This is suggesting that the brain algorithm robustness depends on how many receptors are involved in the elaboration. While similar flickering-eye vibration perceptual instabilities has been reported in various forms in the past, this is the first report where a vibrotactile stimulus is given on the subjects eye and through systematic parameter manipulation. A rigorous model is given to explain the phenomena in a quantitative framework.