Abstract
Even when we stare intently at an object, our eyes constantly make small, involuntary eye movements. However, the incessant motion of the retina that arises goes unnoticed due to perceptual stabilization mechanisms. It remains largely unexplored whether these mechanisms have consequence for visual performance. Observers can group a grid of regularly arranged elements into rows or columns when alternate rows (or columns) are presented with an imperceptible temporal offset, allowing small eye movements to subtly shift the position of the alternate rows or columns (Wallis 2006). We incorporated this temporal row/column grouping task within a visual illusion, which temporarily disables perceptual stabilization mechanisms through a 10Hz flickering annulus of random noise (Murakami 2003). We presented alternate grid elements over two successive display frames, with either no stimulus displayed at other times (brief presentation) or a complete (i.e. alternate elements presented simultaneously) grid displayed both before and after (extended presentation). Observers' ability to correctly group the grid stimulus in accordance with alternate row or column presentations were measured in the presence and absence of perceptual stability (i.e. non-flickering vs flickering annulus) for both grid presentation conditions. For brief presentations, flicker had no measurable effect on temporal row/column grouping (n=12; grouping performance (median): flickering 58.6% vs. non-flickering 58.0%; Wilcoxon signed-rank test, p=0.700). For extended presentations, grouping performance was significantly different between flickering and non-flickering surrounds (flickering 58.6% vs. non-flickering 52.2%; p=0.025). Our findings suggest that perceptual stabilization of small eye movements can have a small, but measurable effect on temporal row/column grouping. Murakami, I. (2003). "Illusory jitter in a static stimulus surrounded by a synchronously flickering pattern." Vision Res 43(9): 957-969. Wallis, G. (2006). "The temporal and spatial limits of compensation for fixational eye movements." Vision Res 46(18): 2848-2858.
Meeting abstract presented at VSS 2018