Barking up the right tree:study shows we can understand dog growls

Scientists discover humans can correctly identify canine emotions — with women better at it than men

By Nicola Davis  /  The Guardian

Thu, May 18, 2017 - Page 13

Humans can determine a dog’s mood by the sound of its growl, scientists have found, with women showing greater ability than men.

While previous studies have found that humans can unpick the context of barks, the latest study investigated whether the same was true of canine grumbles, with some previous research suggesting humans struggle to differentiate between playful and aggressive vocalizations.

“It is an important thing that humans are capable [of recognizing] the emotional state of another species just based on the vocal characteristics,” said Tamas Farago first author of the study from Eotvos Lorand University in Hungary.

To tackle the conundrum, Faragoand colleagues used previously captured recordings of 18 dogs growling in three contexts: guarding food from other dogs, playing tug-of-war with humans, and being threatened by the approach of a stranger. The researchers monitored several features, including the length of each growl and its frequency.

Two sets of the recordings, which included two growls from each context, were played to 40 adults. Each participant was asked to record their impression of the first set of growls on a sliding scale, rating their perception of the dog for five emotions: fear, aggression, despair, happiness and playfulness.

For the second set of recordings, each participant was asked to choose the context of the growl from three options: food guarding, responding to a threat, and play.

The results, published in the Royal Society Open Science journal, show that participants were able to identify on canine emotions, with growls relating to food guarding deemed the most aggressive, and those recorded during play rated higher in playfulness and happiness and lower in fearfulness and despair.

Analysis of the growls revealed that features such as duration, rhythm and pitch appeared to offer clues about the dog’s mood.

“[The participants] had no idea about the actual context of the growl, they just heard the growl and then based on the acoustic structure they could rate it as a happy growl [for example],” Farago said.

Participants were able to correctly classify 81 percent of play growls, 60 percent of the food growls and 50 percent of the threatening growls, with further analysis revealing that often the latter two were confused.

What’s more, the team found that women and dog owners of either sex were better at the task.

“It is known that women have a higher emotional sensitivity, and probably this higher sensitivity can help to differentiate better the context of the growls,” the authors write.

The study concludes that humans are not only able to match emotions to growls, but also to figure out their context.

Holly Root-Gutteridge, an expert in animal communications from the University of Sussex, who was not involved in the research, said the study was an interesting step towards decoding dog communication. The research sheds light on one of the big questions in the field: whether humans are as good at understanding dogs as they are at understanding us.

She said the finding that humans were poorer at telling apart food guarding and threatening-scenario growls from playful ones “is interesting as it means humans recognize the broad context of a growl but may not parse the niceties of defensive versus aggressive threats as well. The results concur with earlier ones that longer growls are more aggressive and that there are audible differences between a ‘let’s play’ happy growl and a ‘my bone, leave it’ defensive one.

“Learning about these differences may help in reducing dog aggression towards humans, as well as improving dogs’ behavior, as we understand better when a threat is real versus playful.”