Why your eyes close shut when you hear a loud noise?
The blinking response to a sudden loud noise is scientifically termed as. The acoustic startle-reflex eye blink. It is a protective mechanism we have developed due to evolution. In ancient times, we were very vulnerable to attacks, and many times. A loud sound meant that we were either being attacked or injured by a falling rock. Now, our eyes being extremely sensitive, they needed protection first. Hence, whenever an intense noise suddenly reaches our ears, within 3 to 8 milliseconds. A cluster of giant neurons called caudal pontine reticular nucleus gets activated. Which eventually activate motoneurons in our brainstem. These motoneurons inform the facial nerves and muscles to close our eyes tightly. Thus preventing them from any kind of harm. Hence, it is our natural reflex to blink in response to a loud bang.