Can animals and pets distinguish between positive and negative sounds from their fellow species and human? A recent study has pointed out that horses, pigs and wild horses can distinguish between negative and positive sounds.
The study by researchers at the University of Copenhagen provides insight into the history of emotional development and opens up interesting perspectives with regards to animal welfare. The researchers found that domesticated pigs and horses, as well as Asian wild horses, can tell the difference, both when the sounds come from their own species and near relatives, as well as from human voices.
Pigs were studied along with boar, which was their wild relatives. Just as in the case of the two related horse species, the pigs clearly reacted to how the sounds of their counterparts were emotionally charged.
To avoid having the domesticated animals react to specific words, positive and negative human speech was performed by a professional voice actor kind of gibberish without any meaningful phrases.
The animals’ behavioural reactions were recorded in a number of categories used in previous studies – everything from their ear position to their movement or lack thereof.
On this basis, the researchers concluded: “Our results show that these animals are affected by the emotions we charge our voices with when we speak to or are around them. They react more strongly – generally faster – when they are met with a negatively charged voice, compared to having a positively charged voice played to them first. In certain situations, they even seem to mirror the emotion to which they are exposed.”
DO ANIMALS HAVE AN EMOTIONAL LIFE?
The researchers also looked into ’emotional contagion” in animals. In behavioural biology, this type of reaction is seen as the first step in the empathy category.
The study was unable to detect clear observations of ’emotional contagion, but an interesting result was in the order by which the sounds where delivered. The Human voices have a direct impact on the emotional state of animals, which is very interesting from an animal welfare perspective. It can also be used as a concrete means of improving animals” daily lives, if those who work with them are familiar with it.
If animals are initially spoken to in a more positive, friendly voice, when met by people, they should react less. They may become calmer and more relaxed, the researchers explained
HOW THE RESEARCHERS DID IT
• The animals in the experiment were either privately owned (horses), from a research station (pigs) or living in zoos in Switzerland and France (wild Przewalski’s horses and wild boars).
• The researchers used animal sounds with a previously established emotion valence.
• The sounds of the living beings and human voices were played to the animals from hidden speakers.
• The sounds were played in sequences with either a positive or negatively charged sound first, then a pause, – and then sounds with reverse valence, i.e. the reverse emotion.
• The reactions were recorded on video, which the researchers could subsequently use to observe and record the animal’s reactions,