You won’t believe what blinking does to your brain’s view of the world!

The intriguing findings from the University of Rochester, published in the prestigious journal Proceedings of the National Academy of Sciences (PNAS), was led by Michele Rucci, a professor in the Department of Brain and Cognitive 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,” explained Rucci in a statement.

This finding shifts our understanding of the seemingly mundane act of blinking into something much more fundamental to visual perception.

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Making the association

The methodology used in the study was both sophisticated and innovative. According to a release from the university, the researchers employed advanced eye-tracking technology to monitor and analyse the eye movements of participants in real time.

This technology allowed them to capture the subtle dynamics of blinking and the associated changes in visual perception.

To deepen their analysis, the team also used computer modelling to simulate how these eye movements affect visual processing.

The models helped predict how blinking could influence the light patterns reaching the retina and how the brain processed these changes.

By comparing the outcomes from these models with the actual data collected through eye-tracking, the researchers were able to draw robust conclusions about the impact of blinking on visual perception.

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Visual restart process

The researchers found that this subtle “visual restart” helped people reset their eyes to be able to detect bigger, more gradual shifts in their field of vision that would otherwise go unnoticed with a prolonged, steady gaze.

This means those brief blinks give a clue to the brain about the overall gist of a scene rather than the fine details.

The first author of the paper from Rucci’s lab, graduate student Bin Yang, stated: “We show that human observers benefit from blink transients as predicted from the information conveyed by these transients.”

While it is generally believed that blinking disrupts visual processing, it in fact amplifies it, compensating for the loss in stimulus exposure.

This study is interesting as it also challenges the conventional wisdom that sight is a purely passive sense where our brains just interpret the visual data streaming in through our eyes.

The research suggested that vision is an active process involving the dynamic interaction of biochemical senses and physical movements just like other senses like smell or touch.

The researchers hence claim that the next time you blink and can’t see anything in front of you for a few microseconds, you should not worry.

Instead, know that it is actually aiding the brain with a high-level overview of the scene before your eyes reset to re-focus on the details.

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What are Indian doctors saying?

Explaining the process of blinking, noted Chennai-based ophthalmologist and oculoplastic surgeon Dr E Ravindra Mohan said, “Rapid and transient closure of the eyelids is the blink of an eye. It is very spontaneous, occurring regularly about 10-15 times a minute.”

He noted that humans blink every four seconds, and don’t really think much about this; it is considered a spontaneous act — not really a thought-out one — in waking life.

The second type of blink, he noted, is the reflex blink. If we see someone coming at us, or if something is thrown towards us, we blink. This is an involuntary action — basically a protective blink — to protect our eyes.

The third type is a voluntary blink, where we can blink whenever we want to, explained Ravindra.

“Any blink is a rapid and transient closure of an eyelid. We all know that blinking helps in tear resurfacing, and there has been a lot of discussion in the scientific literature (and in the mass media regarding the increasing incidence of computer vision syndrome or digital eye strain) about the importance of blinking and how blink rates have come down — when we look at devices — to even 50 percent of the normal rate,” he pointed out.

The study explains that the normal blink lasts a few hundred milliseconds — about a tenth of a second on average. Now, if we have a camera and if the object passes in front of it for this much time, it will be noticed very prominently and easily.

“But if we contrast this with a normal blink, we never come to recognise the fact that we have absolutely no vision for a tenth of a second. This fact is never recognised by us,” explained Ravindra.

“The fact that during the blink we don’t notice the absence of vision is called perceptual constancy. The study shows that the blink ensures that there is a continuity of vision. The effect seems that there is a refreshing of the visual scene due to this perceptual constancy. Without the blink, the visual process would be far more inefficient and inadequate,” he said.

(Edited by Arkadev Ghoshal)