Summary: The frequency of your eye movements, called saccades, determines how fast an item can move before it becomes visible to you. Objects that mimic the frequency and direction of saccades is largely “vanish” from view, showing that our own movements form what we can and can’t see.
People with faster saccadic motions are able to understand faster-moving stimuli, suggesting a link between engine and physical performance. The review highlights how perception is n’t only about what the eyes find, but also about how the body moves, offering new insight into how our sensory and motor techniques are intertwined.
Important Facts:
- Saccade Speed Sets Limits: The faster your saccades, the faster an item may proceed to vanish from view.
- Personal Perception: People with quicker attention movements may see faster-moving items than others.
- Motor-Sensory Link: The physical technique filters out action that mimics eye action, preventing movement smear.
Origin: TUM
If you immediately shift a lens from subject to object, the dramatic change between the two points causes a movement smear that might offer you nausea.
Our vision, nevertheless, do activities like these two or three times per minute. These quick movements are called saccades, and although the physical stimulus during a saccade shifts immediately across the eye, our mind seems to keep it under the helmet: we not perceive the change.
New research shows that the rate of our saccades predicts the speed control in our perception when an item becomes too strong to see.
According to a review published in Character Communications by researchers from the Cluster of Excellence Science of Intelligence ( TU Berlin ), visual stimuli ––think a chipmunk darting around or a tennis ball hit with full force– – become invisible when they move at a speed, duration, and distance similar to those of one of our saccades.
This suggests that the properties of the human sensory program are best understood in the context of the activities of our sight.
When does a moving stimulus became very hard to view?
The limits of how hard an item can be before it becomes visible to us is directly related to the frequency of our own eye movements. Beyond a specific rate, a moving trigger becomes very hard for us to see.
As a result, the rate of our attention motions across a certain distance can be used to determine at what rate a moving signal becomes invisible to us.
And since the rate of our eye movements shifts from person to person, people who make mainly rapid eye movements can also see things moving at higher speeds than individuals with slower eye moves.
This might mean that the best baseball batters, action video game players, or wildlife photographers are the ones with quicker eye movements.
Our movements shape our perception
This result is exciting as it provides first evidence of the idea that our body movements fundamentally shape the abilities of our perceptual system.
“ What parts of the physical world we can sense depends fundamentally on how good our sensors are, ” explains Martin Rolfs, the lead author of the study.
“For example, we don’t see infrared light because our eyes are not sensitive to it, and we fail to see flicker on our screens because they flicker at higher frequencies than our eyes can resolve.
“ 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.
“To show this, we used the body’s fastest and most frequent motions, i. e. the saccadic eye movements that people make more than a hundred thousand times a day. ”
A motion we don’t perceive
Much like a camera movement causes motion in a movie, saccades create movement patterns on the retina.
“ But we never consciously perceive that motion, ” says Rolfs.
“We have shown that stimuli that follow the same ( very specific ) movement patterns as saccades ( while people are holding their eyes still ) also become invisible. So we are basically suggesting that the kinematics of our actions ( here, saccades ) fundamentally constrain a sensory system’s access to the physical world around us. ”
Rolfs explained that this is to be considered an intelligent trait of the visual system, because it remains sensitive to fast motion, but only up to speeds that result specifically from saccades, and these speeds are not seen consciously albeit available to the brain.
“ In simple terms ,the properties of a sensory system such as the human visual system are best understood in the context of the kinematics of actions that drive its input( in this case, rapid eye movements ), ” said Rolfs.
A finely tuned machine
“Our visual system and motor system are finely tuned to each other, but this has long been ignored, ” says Martin Rolfs.
“One of the issues is that the people who study motor control are not the same ones who study perception. They attend different conferences, they publish in different journals – – but they should be talking! ”
This study suggests that our visual system can recognize when a stimulus moves in a way that is similar to our own eye movements, and then filters out the conscious perception of this movement.
This also introduces a new mechanism to explain why we do not see visual motion smear on the retina during eye movements as we would if we were using a camera.
About this visual neuroscience research news
Author: Solveig Steinhardt
Source: TUM
Contact: Solveig Steinhardt – TUM
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Lawful kinematics link eye movements to the limits of high-speed perception ” by Martin Rolfs et al. Nature Communications
Abstract
Lawful kinematics link eye movements to the limits of high-speed perception
Perception requires active sampling of the environment. What part of the physical world can be perceived is limited by the sensory system’s biophysical setup, but might be further constrained by the kinematic bounds of the motor actions used to acquire sensory information.
Here, we tested this fundamental idea for humans ’ fastest and most frequent behavior —saccadic eye movements—which entail incidental sensory consequences ( i. e. , swift retinal motion ) that rarely reach awareness in natural vision.
Using high-speed video projection, we display rapidly moving stimuli that faithfully reproduce, or deviate from, saccades ’ lawful relation of velocity, duration, and amplitude.
For each stimulus, observers perform perceptual tasks for which performance is contingent on consciously seeing the stimulus ’ motion trajectory.
We uncover that visibility of the stimulus ’ movement is well predicted by the specific kinematics of saccades and their sensorimotor contingencies, reflecting even variability between individual observers.
Computational modeling shows that spatiotemporal integration during early visual processing predicts this lawful relation in a tight range of biologically plausible parameters.
These results suggest that the visual system takes into account motor kinematics when omitting an action’s incidental sensory consequences, thereby preserving visual sensitivity to high-speed object motion.
