…it turns out that there’s a good scientific reason why certain sounds set most people’s teeth on edge: human ears are extra sensitive to a particular range of pitches. Although where that sensitivity comes from is still up for debate. In 1986, a group of neuroscientists tried to get to the bottom of these intense reactions by doing what so many researchers do: unpleasant things to volunteers. Specifically, they asked 24 adults to rank a series of 16 sounds based on how unpleasant they thought those sounds were. And although that isn’t a very big sample size, the noises that were consistently rated the nastiest — like the sound of a fork scraping a plate or squealing brakes — all had something in common: They share a frequency range between 2,000 and 5,000 hertz, where our ears happen to be especially sensitive.