Eyes speak volumes through hard sums
Andy Coghlan · The New Scientist · 2013
Giving fully conscious but paralyzed people difficult sums to do might seem like adding insult to injury. But because such brain teasers make the pupils of the eyes involuntarily dilate, it is providing a simple method of conversing. It's been known since the 1960s that the pupil dilates with mental effort, says Wolfgang Einhauser of the Philipps University of Marburg, Germany, and coordinator of the team that has developed a communication system using the phenomenon. All that is needed is a laptop and a camera. The laptop displays a difficult sum, such as 45 x 34. A person attempts to solve the sum only when the answer to a question is yes. If the answer is no, they ignore the calculation. The camera is trained on the person's eyes to detect widening of the pupil. Such dilation thus means the answer to a question is yes, no dilation equals no. In six healthy volunteers used to test and calibrate the system, the procedure worked with up to 99% accuracy.