Pupil Dilation Reveals Better Working Memory
People whose eyes dilated more performed better on tests of working memory
From a scientific perspective, it may sound a bit too fanciful to call our eyes “windows to the soul.” But research suggests that looking into them can, quite literally, offer a peep into a person’s basic cognition.
The 10th Century Persian physician Al-Razi (also known as Rhazes) is often credited with connecting pupil size and light exposure. In the 20th century neuroscientists began to investigate pupils’ connection to deep-brain processes. They found that pupils’ size also fluctuates with attention, arousal and anger—and may even be linked to intelligence. Now a study in Attention, Perception, & Psychophysics suggests that working memory (the executive function that lets us process, remember and use information) correlates with pupil size, too.
Researchers placed study participants in a light-controlled environment and used a specialized eye-tracking tool to measure pupils during a common test for assessing working memory. Participants viewed a sequence of numerals that flashed on a screen for 2.5 seconds each and had to determine whether the current digit matched the one they had seen two digits back.
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Participants whose pupils dilated more performed better on the task—suggesting pupil size does have a connection with working memory. “The same part of the brain that controls this dilation when something stressful triggers our body to become aroused also controls arousal when we are really focused on a task or doing something cognitively effortful, leading to an increase in pupil diameter,” says study co-author Lauren D. Garner, a…
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