my old mit perception ta josh mcdermott and mark hauser propose that humans evolved to prefer consonant sounds over dissonant sounds. the way they show it is by placing monkeys in a V-shaped maze with musical chords playing at one end and cacophonous tones at the other. while monkeys prefer soft sounds to loud ones and happy sounds to sad ones, they have no preference between chords and dissonant notes. they checked by putting five harvard undergraduates in a room with two speakers and told them to wait five minutes, during which everyone went to the harmonious side of the room.