The researchers played each piece, as well as several samples of human music, for 14 tamarin monkeys that hadn’t heard music before. An independent observer recorded monkey behavior for five minutes before and after playing each selection. The monkeys didn’t respond at all to Nine-Inch Nails, Tool or Samuel Barber’s “Adagio for Strings,” but oddly enough, they did become slightly calmer after listening to “Of Wolf and Man” by Metallica.
Monkey music, on the other hand, had a significant and predictable effect on behavior. After listening to the fear-based track, the animals became anxious and upset, as indicated by increased activity and nervous behaviors like urination and scent marking. After hearing the calm music, the monkeys became more relaxed and social.
“It’s not obvious that this would happen, but I don’t think it’s terribly surprising,” said neuroscientist Josh McDermott of New York University, who studies primates and music but was not involved in this study. Because the researchers designed the sounds to share acoustical properties with the noises monkeys make to express emotions, McDermott said it’s natural the animals would respond emotionally.
“I think that the most interesting thing that has come out of this study is some suggestions for animal care,” he said. “It’s very common for people to play music for animals that are in captivity, because they figure that they’ll be interested in it or enjoy it. But our work suggests that they aren’t that interested in human music or prefer not to listen to it at all.” However, if music was tailored specifically to the kinds of sounds that animals are used to hearing, McDermott thinks it might have a more positive effect.
