Pupils constrict at thought of light

摘要

It is the light we think we see that counts. Optical illusions designed to seem brighter than they are make your pupHs constrict a little more. This suggests that we have evolved systems for anticipating dazzling light to protect our eyes. Our pupils' fast response to light appears to occur even without input from the brain. For example, it Is seen in people with damage to the visual cortex. Appearances can be deceptive, though.