Dogs are animals with a marked expressiveness, inherited from the wolves from which they descend and then shaped over thousands of years of coexistence with humans. It is often said that dogs lack only the gift of speech, precisely by virtue of their extensive repertoire of expressive movements, and no dog owner has ever doubted that the typical guilty-dog look their animal assumes is put on deliberately to communicate something. The varied non-verbal language of dogs, in short, is hardly a surprise. A new study has revealed, however, that dogs produce more facial expressions when a human is watching them, and that these expressions are therefore used to communicate and, perhaps, to manipulate us.

I know you're watching me

The study, conducted by researchers at the Dog Cognition Centre at the University of Portsmouth and published in Scientific Reports, demonstrated for the first time that dogs change their expression when they know they are being watched by a human. "We can now be confident that the production of facial expressions in dogs depends on the attentional state of their audience and is not simply a result of the animal's level of excitement," said the study's lead author, canine cognition expert Juliane Kaminski. "The results suggest that dogs are sensitive to human attention and that their expressions are active attempts to communicate."

Voluntary expressions

The researchers therefore believe that dogs' expressions are assumed with an explicit communicative intent and are not involuntary. Many mammals do produce facial expressions, but in most cases — including many human expressions — these are involuntary and depend on the individual's emotional state rather than on their interaction with an observer. Kaminski thinks it is possible that dogs' facial expressions changed during the domestication process.

The irresistible puppy face

The researchers studied 24 pet dogs of different breeds, aged between 2 and 12 years. The most frequently used expression among the dogs analysed for the study was the classic sad face, achieved by raising the eyebrows and thereby enlarging the eyes, which come to resemble those of a puppy. In doing so, the dogs activate what Konrad Lorenz called the "baby schema," which makes young animals irresistible to our eyes.

Dogs keep an eye on us

Our species has shared its existence with dogs (Canis lupus familiaris) for thousands of years; during this long process of mutual domestication, which changed the fate of both species forever, dogs have learned to observe us and monitor our behaviour.

The experiment

The researchers analysed the dogs' expressions using a dedicated system called DogFACS, capable of standardised coding of facial changes linked to muscle movement. To carry out the experiment, the dogs were brought into a room and placed near a person they had never met before, who adopted four different behaviours. This study provides us with further insights into dog cognition, but despite the millennia spent side by side, their minds still hold mysteries.