Why scientists think you should speak politely to animals

They can’t talk back but they probably can’t understand the words we’re saying, but that doesn’t mean that animals don’t feel what we’re saying to them. In a new study, researchers at the University of Copenhagen found that horses, pigs, and wild horses were able to distinguish between positively and negatively charged sounds, including those in human speech, as evidenced by their behavior.

“The results showed 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,” behavioral biologist Elodie Briefer of the University of Copenhagen’s Department of Biology said in a statement.

Humans are innately emotional and social creatures. In fact, we’re so social that during our interactions, our emotions can synchronize with the people we’re talking to. If I feel sad and we interact, you may feel sad too. If I’m smiling and being very positive while we have a conversation, chances are the emotion will rub off on you. This phenomenon is known as emotional contagion or mirroring and can be triggered by facial expressions, indirect human interactions, and by observing other people’s behavior in direct and indirect interactions.

Part of the reason why the researchers embarked on this study was to see whether animals could also be affected by emotional transfer. The animals from the experiment involved privately owned horses, pigs from a research station, as well as wild Przewalski’s horses and wild boars from zoos in Switzerland and France.

The animals were subjected to animal call sounds and human voices played from high-fidelity hidden speakers. The sounds were played in sequences with either a positively or negatively charged sound first, followed by a pause, and then sounds of opposite emotions to the initial record. In order to avoid any bias introduced by reactions to specific words that domestic animals might know, the human voices were recorded by a professional actor who uttered emotionally-charged gibberish, which conveyed joy and amusement (positive), as well as anger and fear (negative), but without a specific meaning attached to the phrases.

Research shows that animals can react to positively and negatively charged sounds, suggesting emotional contagion.