Can you tell just from a whine, grunt, bleat, or a moo whether a hoofed animal is happy or in distress? If you can, it might be a sign that you are particularly empathetic – or you spend a lot of time around animals.
A study led by ethologist Elodie Briefer from the University of Copenhagen in Denmark found that people who had higher empathy scores were better at identifying animal emotions from sound alone.
The study follows a similar investigation published by Briefer earlier this year, which supported speculations that animals hear and respond to the emotion in our own voices.
Briefer and her team collected recordings of vocalizations from domestic animals (including pigs, horses, goats and cattle) and wild animals (including wild boars and wild Przewalski's horses).
Some of these recordings were associated with positive experiences, such as an animal anticipating food or being reunited with a friend.
Other sounds were made when the animal was afraid, under stress, or socially isolated.
The heart rate of the domestic animals and the movements of the wild animals were used as measures of how strongly the emotion was being felt, or the 'emotional arousal', at the time the sound was made.
Human voices were also included in the mix. The researchers created some meaningless words and hired actors to say them in positive and negative tones of voice.
Two sounds from the same animal (or human actor) – one with low arousal and one with high arousal – were played to 1,024 study participants from 48 countries.
People were also asked to complete an empathy questionnaire based on the interpersonal reactivity index.
This index measures four empathetic traits: their tendency to adopt other people's points of view, feel sympathy for others, experience distress when others are in need, and imagine themselves in fictional situations.
Overall, people correctly interpreted the meaning of animal sounds more than 50 percent of the time, which is better than random chance.
People were more reliable when detecting the level of emotional arousal than the type of emotion in animals. This could be because arousal is a stress response that is conserved through evolution in mammals, and is generally represented by a high-frequency noise, says Briefer, the senior author on the study.
Gender and education level had no effect on people's ability to interpret animal noises, but age did, with people aged 20 to 29 being the best, and ability declining with age.
Humans were more attuned to the sounds of other humans and domestic animals compared with wild animals. And people who worked closely with animals were better at understanding them, suggesting that cross-species communication can be improved through exposure and practice.
People who scored highly for empathy were better able to understand the meaning of the animal sounds.
This finding mirrors another study in which humans who had greater empathy towards cats were better at discerning whether their meows were associated with positive experiences (like being brushed) or negative experiences (like being isolated).
It's possible to train people to improve their understanding of the emotional lives of animals, says Briefer.
"When students try the test in class, they obtain an average of 50 percent of correct answers on the first try," she says.
"After we talk about the sounds and knowledge that we have about animal vocalizations, they improve. On their second attempts, they typically get above 70 percent correct."
This research suggests all us mammals have a shared emotional system.
This paper was published in Royal Society Open Science.