New Research Challenges Traditional Views
By UNIVERSITY OF ROCHESTER
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Given that blinks prevent an image of the
external scene from forming on the retina, it’s a peculiar quirk of evolution
that we spend so much time in this seemingly vulnerable state—especially
considering that eye blinks occur more frequently than necessary just to keep
our eyes well lubricated.
So why is blinking important?
Researchers from the University of Rochester
investigated the curious case of blinking and found that eye blinks aren’t just
a mechanism to keep our eyes moist; blinks also play an important role in
allowing our brains to process visual information. The researchers published
their findings in the Proceedings of the National
Academy of Sciences.
“By modulating the visual input to the retina, blinks effectively reformat visual information, yielding luminance signals that differ drastically from those normally experienced when we look at a point in the scene,” says Michele Rucci, a professor in the Department of Brain and Cognitive Sciences.
The big picture—in the blink of an eye
Rucci and his colleagues tracked eye
movements in human observers and combined this data with computer models and
spectral analysis—analyzing the various frequencies in visual stimuli—to study
how blinking affects what the eyes see compared to when the eyelids are closed.
The researchers measured how sensitive humans
are at perceiving different types of stimuli, such as patterns at different
levels of details. They found that when people blink, they become better at
noticing big, gradually changing patterns. That is, blinking provides
information to the brain about the overall big picture of a visual scene.
The results show that when we blink, the
rapid motion of the eyelid alters the light patterns that are effective in
stimulating the retina. This creates a different kind of visual signal for our
brain compared to when our eyes are open and focused on a specific point.
“We show that human observers benefit from
blink transients as predicted from the information conveyed by these
transients,” says Bin Yang, a graduate student in Rucci’s lab and the first
author of the paper. “Thus, contrary to common assumption, blinks improve—rather
than disrupt—visual processing, amply compensating for the loss in stimulus
exposure.”
Revising a view of vision
The findings further reinforce the growing
body of research in visual perception from Rucci’s laboratory, highlighting
that how humans see is a combination of sensory input and motor activity. When
we smell or touch, for instance, our body movements help our brain understand
space. Researchers previously believed seeing was different, but Rucci’s
research lends support to the idea that vision is more like the other senses.
“Since spatial information is explicit in the
image on the retina, visual perception was believed to differ,” Rucci says.
“Our results suggest that this view is incomplete and that vision resembles
other sensory modalities more than commonly assumed.”
Reference: “Eye blinks as a visual processing
stage” by Bin Yang, Janis Intoy and Michele Rucci, 2 April 2024, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2310291121
The study was funded by the National Institutes of Health.
