ИСТИНА

It was shown that drift illusions are strongly affected by eye movements (Kitaoka, 2010). The aim of our study was to reveal the role of eye movements in “spine drift” illusion perception. The original display of the illusion was changed to construct four modified variants: each spine of the central square was rotated at 30°, 60°, 90° for the 1-3 variants respectively and all spines of the central square were oriented in random order for the 4th variant. The observers were asked to look at each displays for 10 sec and then to estimate the illusion strength on a scale of 1-5. During the performance eye movements were recorded. The results revealed that the illusion strength was highest for the original display and then decreased gradually from the 1st to the 3rd variants. The data for the 4th variant were medium in value. Differences in fixation durations and microsaccade counts were correlated with subjective ratings. No significant differences for saccade counts were found. Our results indicate that the measured micro and macro movements may be considered as reliable indicators of the illusion perception