Why do some chords sound sweet but others make you wince? Well it appears our ears - or at least the ears of 250 Minnesota undergrads - prefer chords containing harmonically related frequencies, according to a study in the journal Current Biology. Even a simple note on my guitar has an array of harmonic frequencies. But the frequencies have a special harmonic relationship, which is why you hear it as a single sound with a single pitch. The chords the students liked best have frequencies with that harmonic relationship too—all the frequencies are integer multiples of a common fundamental frequency. And the researchers say our brains might like these chords because their frequencies resemble those of a single harmonic note. The students were less fond of inharmonic chords like. But the researchers say it's not that rough, wobbly quality, called beating, that turns us off. It’s mostly because the chords aren't harmonic. These preferences aren't completely innate though. Musically trained students found harmonic frequencies more pleasing - they're huge in western music. But an ensemble of gamelan masters, who play inharmonic instruments like gongs, might beg to differ.