What is the most annoying sound ever? Finger nails on a chalk board? Nope...

Scientists studying the brain‘s reaction to sound have determined the piercing screech of a knife against a glass bottle to be the human ear’s worst nightmare.

A research team at the University of Newcastle in Australia examined brain activity in a group of volunteers, who listened to 74 recorded sounds under an MRI machine and ranked each experience.

The top 5 most irritating sounds are:

#5.)  Nails on a chalkboard.

#4.)  Rubbing a ruler against a glass bottle.

#3.)  Writing on a chalkboard with chalk.

#2.)  Dragging a fork across glass.

#1.)  Rubbing a knife against a glass bottle.

Listen below (if you dare!) and tell us what sound is the most irritating to you! The most irritating to me? No doubt, ALL OF THEM!

via Scientists Find Harshest Sound in World: Listen - ABC News.