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SODid the lines look like they’re moving? This is sigma motion, a visual illusion where a stationary pattern, often black-and-white stripes, appears to move when your eyes smoothly track across it.
What’s happening?
Your brain isn’t just reading the image from your retina, it’s also using an internal signal about your eye movement, called efference copy, to interpret what you see. When the pattern flips rapidly during smooth pursuit, the visual system can experience motion even though nothing in the image is actually moving.
This illusion is a great reminder that vision is not just about what hits the eye, it’s also about how the brain predicts and interprets movement.
Credits:
Sigma motion was coined by O. J. Grüsser. Research on the interaction between eye movements and apparent motion was advanced by James Pomerantz and later work by Adler et al.
#sigma #visual #neuroscience #perception #opticalillusion
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