Blinking may do more than just keep our eyes healthy
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Blinking serves a crucial physiological function, by clearing debris from our eyes and keeping them lubricated. But now, scientists have found it may also have a cognitive role.
In 1945, Arthur Hall at the University of Sheffield in the UK reported on the frequency of blinking as people read aloud, finding that it mostly coincided with gaps in the print. He suggested that blinking may help people take pauses as they read.
To expand on this idea, Louisa Bogaerts at Ghent University in Belgium and her colleagues analysed data gathered previously for the Ghent Eye Tracking Corpus study, in which 15 people were monitored as they silently read an Agatha Christie novel across four sessions, collectively blinking 30,367 times.
“The results clearly show that we do not blink randomly when reading,” says Bogaerts.
The team found that the participants were less likely to blink after reading words that frequently occurred in the text compared with those that occurred infrequently. “Increased blinking after fixating on lower-frequency words suggests that cognitive effort influences blinking behaviour,” says Bogaerts. Blinking may provide a “cognitive break”, the researchers wrote in their paper.
They also found that blink rates were 4.9 times higher at any punctuation marks, on average, compared with other positions in the text. They were also 3.9 times higher at the end of a line on a page and 6.1 times higher when punctuation marks and line endings coincided.
“Increased blinking at punctuation marks and line endings likely reflects that these are natural attentional breakpoints – we align with these breakpoints in the text and take a break to blink,” says Bogaerts. “Together, these findings support the hypothesis that blink timing during reading is not random, but strategically aligned with the cognitive demands posed by the text.”
“Blinks afford a momentary pause in visual input to allow new information to be integrated,” says Paul Corballis at the University of Auckland in New Zealand. “I think it remains some way off, but I can envisage using online tracking of blinks and eye movements to monitor situational awareness in pilots or air-traffic controllers, or anyone who needs to [re]main vigilant while monitoring and making sense of incoming data – perhaps including the ‘drivers’ of driverless cars.”
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