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December 28, 2012

BehindTheMedspeak: Are your eyes closed? 'Cause you must be blinking.

"... our eyes are closed for roughly 10% of our waking hours overall."

That got my attention during the other 90%.

Excerpts below from a December 24 Smithsonian.com story about our heretofore unappreciated dark time.

The average person blinks some 15-20 times per minute — so frequently that our eyes are closed for roughly 10% of our waking hours overall.

Although some of this blinking has a clear purpose — mostly to lubricate the eyeballs and protect them from dust or other debris — scientists say that we blink far more often than necessary for these functions alone. Thus, blinking is a physiological riddle. In a paper published today in the Proceedings of the National Academy of Sciences, a group of scientists from Japan offers up a surprising new answer — that briefly closing our eyes might actually help us to gather our thoughts and focus attention on the world around us.

The researchers came to this hypothesis after noting a fact revealed by previous research on blinking: the exact moments when we blink aren't actually random — people tend to blink at predictable moments. For someone reading, blinking often occurs after each sentence is finished, while for a person listening to a speech it frequently comes when the speaker pauses between statements. A group of people all watching the same video tend to blink around the same time, when action briefly lags.

As a result, the researchers guessed that we might subconsciously use blinks as a sort of mental resting point, to briefly shut off visual stimuli and allow us to focus our attention. To test the idea, they put 10 different volunteers in a fMRI machine and had them watch the TV show "Mr. Bean" (they had used the same show in their previous work on blinking, which showed that it came at implicit break points in the video). They then monitored which areas of the brain showed increased or decreased activity when study participants blinked.

Their analysis showed that when the Bean-watchers blinked, mental activity briefly spiked in areas related to the default network — areas of the brain that operate when the mind is in a state of wakeful rest, rather than focusing on the outside world. Momentary activation of this alternate network, they theorize, could serve as a mental break, allowing for increased attention capacity when the eyes are opened again.

To test whether this mental break was simply a result of the participants' visual inputs being blocked rather than a subconscious effort to clear their minds, the researchers also manually inserted "blackouts" into the video at random intervals that lasted roughly as long as a blink: they observed that the brain areas related to the default network were not similarly activated. Blinking is something more than temporarily not seeing anything.

Though far from conclusive, the research demonstrates that we do enter some sort of altered mental state when we blink — we're not just doing it to lubricate our eyes. A blink could provide a momentary island of introspective calm in the ocean of visual stimuli that defines our lives.

Below, the abstract of the original paper.

Blink-related momentary activation of the default mode network while viewing videos

It remains unknown why we generate spontaneous eyeblinks every few seconds, more often than necessary for ocular lubrication. Because eyeblinks tend to occur at implicit breakpoints while viewing videos, we hypothesized that eyeblinks are actively involved in the release of attention. We show that while viewing videos, cortical activity momentarily decreases in the dorsal attention network after blink onset but increases in the default-mode network implicated in internal processing. In contrast, physical blackouts of the video do not elicit such reciprocal changes in brain networks. The results suggest that eyeblinks are actively involved in the process of attentional disengagement during a cognitive behavior by momentarily activating the default-mode network while deactivating the dorsal attention network.

December 28, 2012 at 12:01 PM | Permalink


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Comments

A far simpler explanation would be that during our long mammalian (or even vertebrate?) evolution, there was selection for blinking during the milliseconds when action was noticeably paused, allowing a meaningful survival and action advantage due to blinking then not being required when prey was escaping or predators chasing. Blinking during non-crucial moments would mean that although you might have additional blinks over what is strictly necessary, your average eat or be eaten mammal would be ready for any action with eyeballs ready-lubricated and clean.

Unless the researchers actually demonstrate processing coinciding with pause blinks, I suspect Occam's Razor would favour this explanation over "processing".

Like all biological explanations, going from describing behaviour to actually providing solid evidence for why this happens requires some serious scientific digging. Otherwise it's just a cool idea.

Posted by: d | Dec 29, 2012 2:11:49 PM

Very interesting, what Avo said.

I love this little clip of Michael Caine describing, in an acting class, his technique of not blinking:
http://www.youtube.com/watch?v=UTMRufBXhCY

If I'm having an intense discussion - argument, if you will - with someone, I (try to) do the not blinking. It also strengthens your stance, or at least it maintains your apparent focus and conviction, if you don't swallow and don't look away during a tirade, or, uh, ideally, softly-spoken point of view. Giveaways of nervousness or uncertainty. Or, if I'm honest, I just usually say "asshole" and walk away.

Oh, while I'm on the subject of arguments, this is my all time favorite fight in the whole world:
http://www.youtube.com/watch?v=7tUKMdLdLvM

"I,an itching palm?!?" cracks me up every time.

Posted by: Flautist | Dec 28, 2012 5:15:37 PM

Now, that's a fascinating bit of work. I've observed many, many, many people blink just before they lie. I've seen the phenoma so many times that I went to the trouble of reading Dr. Paul Ekman's published work.

The fMRI studies hold real promise. How much data do we transmit non-verbally?

Posted by: 6.02*10^23 | Dec 28, 2012 2:12:17 PM

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