Researchers develop a mental type writer based on pupil-size changes

s.mathot writes: Researchers from France and the Netherlands have developed a way to—literally—write text by thinking of letters. (Academic paper [open access], non-technical blog, YouTube video) This technique relies on small changes in pupil size that occur when you covertly (from the corner of your eye; without moving your eyes or body) attend to bright or dark objects. By presenting a virtual keyboard on which the 'keys' alternate in brightness, and simultaneously measuring the size of the eye's pupil, the technique automatically determines which letter you want to write; as a result, you can write letters by merely attending to them, without moving any part of your body, including the eyes.