When you get goosebumps from screeching violins in a horror movie or feel your spirits lifted by an upbeat pop song, you’re doing something that scientists have rarely observed in the animal kingdom: You have different emotional responses to different types of music. Now pigs provide compelling new evidence that animals can respond emotionally to music as well. The finding could lead to ways to improve their welfare on farms.
“This is a really good study” showing that animals are more emotionally attuned to music than people think, said Charles Snowden, 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 nice to see this empirical work to support it.”
Music is sometimes used as enrichment for farm and other captive animals. And Snowball the dancing cockatoo likes to boogie to the Backstreet Boys. But whether these creatures have a genuine emotional response to the tunes is unclear.
That’s the goal of the new study — but with pigs. Co-author María 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 animal welfare challenges in factory farms .
In the new study, Ceballos’ colleague, Berardo de Jesus Rodríguez, a veterinarian and musician at the University of Antioquia, Medellin, composed 16 pieces of music that included piano, strings, wind instruments and percussion that were mostly consonant or dissonant. To humans, consonant music tends to sound nice and smooth—think of a C major chord—while dissonant music tends to sound jarring and uncomfortable, like an Alfred Hitchcock score Psycho.
The team then filmed six litters of 10 to 12 young pigs listening to music through a loudspeaker in a university pig farm. The musical pieces, each lasting about 3 to 5 minutes, were performed in random order with a 3-minute break between them.
The researchers scored the pigs’ body language along 20 emotional parameters, including “pleasure” and “unpleasantness,” using an approach called qualitative behavior assessment (QBA). The method involves looking at the posture, behavior and interaction of the animal with its environment. For example, QBA can distinguish pigs given the anti-anxiety drug azaperone from those that are not, as they consistently appear more visually curious and less nervous. Stressed animals with higher heart rate and body temperature can also be visually identified as more agitated and restless by QBA.
Pieces of consonant music are associated with pigs experiencing positive emotions, while dissonant music is associated with negative emotions, the team reported this month in Scientific reports. “And so we discovered that yes, music generates different emotions,” says Ceballos. (The pigs’ reactions to the different music can be seen in the video above.)
However, animal welfare scientist Jun Bao of Northeast Agricultural University in China is skeptical that Ceballos’ team has detected emotions. He recently found that exposure to string and brass music increased play and tail wagging in pigs, which he saw as signs of “positive mood.” However, he says it is not clear whether pigs labeled as “happy” or “restless” by the QBA are actually experiencing these emotions.
Snowden says emotional descriptions are a matter of interpretation. In his own work, he has seen monkeys shake their heads, jump quickly between perches, and their fur bristle in response to music. “We didn’t use the word emotion,” he says, “but they exhibited behavior that we thought was indicative of anxiety.”
Ceballos hopes the study will help researchers create well-being-enhancing music tailored for a specific species. Bao agrees that music can probably be therapeutic for stressed animals. However, he is not sure about its usefulness in healthy animals, which may eventually lose interest. “But it’s really interesting because if it works, it will be the most convenient and inexpensive way for them to enrich the environment.”