What Is the Fastest Sense in Humans?

Which is a human’s fastest-reacting sense? Scientists rating the speed associated with the brain’s recognition of sight, sound, taste, smell and the sense of touch have found that hearing is No. 1. Forget about the speed of light vs. the speed of sound; the only thing that matters is how long it takes for information to reach the brain, and some parts of the ear -- such as the stapes reflex, which protects against loud noises -- engage within .025 seconds. That’s 10 times faster than the .2 seconds it takes for the brain to understand the light that reaches the eye, or the .2 seconds it takes for the brain to acknowledge a touch.

Converting sound to impulses:

• We hear when sound waves are funneled down the external ear canal and strike your eardrum, causing it to vibrate. The vibrations are passed to the three small bones of the middle ear, which transmit them to the cochlea.
• The cochlea contains tubes filled with fluid. Inside one of the tubes, tiny hair cells pick up the vibrations and convert them into nerve impulses that are delivered to the brain via the auditory nerve.
• A cochlear implant helps people with hearing loss. They convert sound signals into electrical pulses that stimulate the hearing nerve and go straight to the brain. A MED-EL cochlear implant sends pulses at speeds up to 50,704 times per second.