Anecdote doesn’t count as evidence in the scientific community, so no matter the number of personal tales you have of how your canine companion understands you, there is still a debate among scientists over whether dogs can read our emotions. While this latest study is by no means the final nail in the coffin, it does bolster the idea that they can.
Published in Biology Letters, researchers from the U.K. and Brazil found that dogs are capable of combining both sound and visual information in order to differentiate between positive and negative emotions in both dogs and humans. While previous work has found some animals, like certain primates, can do this with other members of the same species, the researchers claim this is the first time such an ability has been demonstrated across the species barrier, discounting humans.
To reach these conclusions, the researchers rounded up 17 adult dogs of various breeds and simultaneously gave them two types of emotional information: auditory and visual. This consisted of paired images of human or dog faces, which showed either positive/playful or negative/aggressive expressions. At the same time, the researchers played a human talking or dog barking in a manner that either matched the facial expression, or contradicted it.
Importantly, the dogs weren’t given any training before being put on trial, so this should rule out that particular outcomes are simply down to learning, and the faces were novel. The human speech was also in a language – Brazilian Portuguese – the dogs were unfamiliar with to make sure they weren’t cheating and simply drawing on past experiences.
Examples of images used in the study. Albuquerque et al., Biology Letters 2016.
The researchers argued that the length of time spent gazing at the images should inform of whether the animals are able to integrate the two types of sensory information in the recognition of emotion. This kind of test is an established methodology and has been used in studies involving other animals. And as you might expect, what they found supported the notion that pooches are indeed in tune with our moods.
Dogs much preferred looking at the faces whose expression matched the emotion conveyed by the vocalization, spending significantly longer gazing upon these images compared to the mismatched ones. And this was consistent regardless of the sex of the image, species of dog, or whether the emotion was happy or angry. That said, they did show a preference for dog faces over human.
“Our study shows that dogs have the ability to integrate two different sources of sensory information into a coherent perception of emotion in both humans and dogs,” study author Dr Kun Guo from the University of Lincoln said in a statement. “To do so requires a system of internal categorization of emotional states. This cognitive ability has until now only been evidenced in primates and the capacity to do this across species only seen in humans.”
It does make sense that dogs are able to read our moods – the capacity to do so would help in the establishment and maintenance of relationships between man and his best friend. Though, the researchers do point out that humans could have selected for such traits during domestication. Regardless, the study shows that the ability may be more common than thought, and not a uniquely human characteristic.