When you shudder at the screeching violins in a horror movie or feel your spirits lifted by a soulful pop song, you’re doing something that scientists have rarely noticed in the animal kingdom: having different emotional responses to different types of the music. Now, pigs are providing compelling new evidence that animals can also respond emotionally to music. The discovery could lead to ways to improve their welfare on farms.
“It’s a really neat study” showing that animals are more emotionally attuned to music than people think, says Charles Snowdon, a psychologist and animal behavior expert at the University of Wisconsin, Madison, who was not involved in the work. . “We’ve been trying to argue this for a decade, so it’s great to see that this empirical work supports it.”
Music is sometimes used as enrichment for farm and other captive animals. And Snowball, the dancing cockatoo, likes to boogie the Backstreet Boys. But whether these creatures have a real emotional response to the tunes is unclear.
That’s what the new study set out to do — but with pigs. Co-author Maria Camila Ceballos, an animal welfare scientist at the University of Calgary, says she and her colleagues chose these animals because they are highly intelligent and social and face serious welfare challenges in factory farms.
In the new study, Ceballo’s colleague Berardo de Jesús Rodríguez, a veterinarian and musician at the University of Antioquia, Medellín, composed 16 pieces of music with piano, strings, wind instruments and percussion that were mostly consonant or dissonant. To humans, consonant music generally sounds pleasant and calm—think a C major chord—while dissonance tends to sound jarring and unpleasant, such as a score by Alfred Hitchcock PSYCHO.
The team then filmed six litters of 10 to 12 young pigs listening to music through a loudspeaker on a university pig farm. The pieces of music, each lasting about 3 to 5 minutes, were played randomly with a 3-minute break in between.
The researchers assessed the pigs’ body language on 20 emotional parameters, including “content” and “anxious” using an approach called qualitative behavior assessment (QBA). The method involves watching an animal’s posture, behavior and interaction with its environment. For example, QBA can distinguish pigs that have been given the anti-anxiety drug azaperone from those that have not, because they consistently appear more visually curious and less nervous. Stressed animals with higher heart rates and body temperatures can be visually identified as more anxious and distressed through QBA.
Pieces of consonant music were associated with pigs experiencing positive emotions, while dissonant music was associated with negative emotions, the team reports this month in Scientific Reports. “So we found that, yes, music generates different emotions,” says Ceballos. (Pigs’ reactions to different music can be seen in the video above.)
Animal welfare scientist Jun Bao of Northeast Agricultural University in China is skeptical that Ceballo’s team detected emotions, however. He recently found that exposure to string and wind music increases play and tail wagging in pigs, which he sees as signs of a “positive mood.” However, he says it’s not clear that pigs labeled as “happy” or “anxious” through QBA actually experience those emotions.
Snowdon says that emotional descriptions are a matter of interpretation. In his work, he has seen monkeys shake their heads, jump rapidly between takes, and raise their fur in response to music. “We didn’t use the word emotion,” he says, “but they showed behaviors that we think are indicative of anxiety.”
Ceballos hopes the study will help researchers create well-being-enhancing music tailored to a specific species. Bao agrees that music can probably be therapeutic for stressed animals. However, he is not sure of its usefulness with healthy animals who may eventually lose interest. “But it’s really interesting because if it works, it would be the most convenient and cheapest way to enrich their environment.”