Can't keep up? Your eyes may be to blame, new study finds

CTV News

12-05-2025

A new study shows that the speed of eye movements predicts the speed limit of perception. (Photo adapted by Martin Rolfs)
New research suggests that the fastest motion you can perceive may depend on how quickly your eyes can move.
Imagine a chipmunk darting across your yard or a tennis ball flying past your face. If they move fast enough, they'll seem to vanish — not because they're too far away, but because your eyes can't keep up.
In a study published in Nature Communications, researchers from Germany's Cluster of Excellence Science of Intelligence (TU Berlin) found that when an object moves at the same speed and pattern as a rapid eye movement — known as a saccade — it can effectively disappear, even when you're staring right at it.
Saccades are tiny, lightning-fast shifts in gaze that happen thousands of times a day. We're usually unaware of them, but the brain actively filters out the visual blur they cause — a phenomenon called saccadic omission.
To test this, researchers showed high-speed patterns that matched typical saccade movements, while participants kept their eyes still. Most couldn't see the motion when it followed the usual speed and distance of eye shifts — but those with faster eye movements could detect it.
'What parts of the physical world we can sense depends fundamentally on how good our sensors are,' said Martin Rolfs, lead author of the study, in a press release by Science of Intelligence.
'In this paper, however, we show that the limits of seeing are not just defined by these biophysical constraints, but also by the actions and movements that impose changes on the sensory system.'