Resumen de Why we have better eyesight at twilight
Our sight is sharpest at dawn and dusk--and now we may know why. It is not a result of changes within our eyes, but of how the brain processes visual signals. To find out why, Christian Kell of Goethe University in Germany and his team asked 14 men to spot when dim crosshairs flashed up on a screen at six different times of day. They also had their brains scanned, both as they did the task and while they rested. There were two noticeable peaks in their performance on the visual test: at 8.00 am and 8.00 pm, roughly corresponding to the time of sunrise and sunset.
