Pupil Tracking Being Used to Discover Why People Blink
For those of our readers who have never listened to the show Radiolab on WNYC and National Public Radio, I highly recommend you do. A recent episode of the show, which is hosted by Jad Abumrad and Robert Krulwich, focuses on blinking and why humans do it. It’s commonly assumed that humans blink to lubricate the eyes – to moisten the eyeball so it doesn’t dry out. As it turns out, a person’s blink rate is the same whether they’re in a dry place, such as a sauna or desert, as when they’re in a more humid place. If the common assumption were correct, wouldn’t it be the case that an individual might need to blink more often in a drier area? The show’s hosts report that scientists, with the help of pupil tracking technology, have sought out to investigate the true reason behind why humans blink by recording measurements on blinking and blink frequency.
The short podcast goes on to investigate when and why people blink, and while it remains a mystery to researchers, there are some very interesting and reasonable theories proposed.
The story begins with an interview with Walter Murch, a well-respected film editor and sound mixer who has edited classic films like The Godfather and Apocalypse Now. Murch tells a story from a late evening when he was working on the Francis Ford Coppola film The Conversation back in the early 1970s. Film gives the illusion of being one continuous movement, but as we all know, movies are made up from a multitude of various scenes and cuts, spliced together to make it appear seamless. Murch describes a realization he had while sitting in his lab editing a scene. Murch watches, stops, cuts, rewinds, watches, stops, and cuts again, all the while making edits by feel. To make one cut, he’ll run the film through a few times, each time hitting stop when his instinct tells him to. “If I’ve hit that cut button on the same frame twice in a row,” he explains, “that tells me I’m probably where I should be.” While working one night, Murch had an epiphany. He consistently made the cuts at same exact moment the character blinks. Blink…cut, blink…cut. But what does this mean? Well, maybe nothing for someone less perceptive, but Walter Murch, being curious as he is, formed a theory that, perhaps, blinking is a kind of “hidden punctuation to thought or storytelling.” Why would it be so consistent? And is there anything to it scientifically?
The Radiolab hosts then move to an interview with two Japanese researchers who noticed a similar consistency during eye-blink research they performed on moviegoers. In their research, they hoped to solve this mystery. Utilizing eye tracking/gaze tracking applications, the researchers gathered subjects together and hooked each person to a device that mounts on the top and bottom eyelids to record a strong electrical signal which can be used to analyze when a subject blinks. The subjects were then shown a movie – Mr. Bean, which was selected because it is quite easy to understand the plot without sound. The scientists observed the people watching movies, recording their blinks as they watched. And what they found was equally curious: each person blinked at the same points in the movie. In addition, the timing of their blinks occurred at the same time – one third of subjects blinked at the exact moment in the movie. The show’s hosts illustrate this fascinating observation by asking listeners to imagine sitting in a movie theater along with 200 other people, and “with each unconscious blink you make, 70 other people make that blink with you.”
Why does this happen? The researchers think that what seems to be happening is the audience gets in touch with the story, and perhaps intuit the narrative flow, aligning their blinks so they fall into the gaps – at a conclusion of an action by Mr. Bean, at the conclusion of a task, when a door closes, when an empty street is shown, when the action breaks. Their theory is that, aside from not wanting to miss the story itself, blinking might be related to visual punctuation or ways of thinking. Are we synching with the thoughts of the film editor – someone like Walter Murch, an artist of the edit? But why would we need to do that? This, no one knows. But perhaps, the researchers report, it is because humans can only process life in chunks. Maybe we break up the flow of information into shorter chunks to make it more effective. Or maybe its done for sensory processing or memorizing. It’s worth noting, however, that many of the questions raised could be studied with eye-tracking technology.
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