Tag Archives: facial expressions

Our ability to read dogs’ facial expressions is learned, not innate

In a recent study published in Scientific Reports, a team of researchers from Germany and the United Kingdom assessed how experience with dogs affects humans’ ability to recognize dog emotions. Participants who grew up in a cultural context with a dog-friendly attitude were more proficient at recognizing dog emotions. This suggests that the ability to recognize dogs’ expressions is learned through age and experience and is not an evolutionary adaptation.

Facial expressions study

The study used photos of dogs with wolf-like faces and upright ears for emotion recognition © Juliane Bräuer

Dogs were the first domesticated animal, with humans and dogs sharing more than 40,000 years of social interactions and life together. According to the co-domestication hypothesis, this process allowed humans and dogs to evolve special emotional signals and cognitive skills that favor mutual understanding. We know, for example, that over the millennia, dogs have evolved the ability to understand human words, iconic signs, and other gestures, and research has shown that dogs can even use tone of voice and facial expressions to recognize human emotions. Beyond personal testimony from dog lovers, however, little attention has been paid to how well humans can understand their canine counterparts.

In the current study, led by Federica Amici of the Max Planck Institute for Evolutionary Anthropology and Juliane Bräuer of the Max Planck Institute for the Science of Human History, the researchers set out to understand how well humans can understand the emotional displays of dogs, and where that understanding comes from.

How well do we understand our species’ best friend?

In order to test how well humans can understand the emotions behind dog facial expressions, researchers collected photographs of dogs, chimpanzees, and humans displaying either happy, sad, angry, neutral, or fearful emotions as substantiated by the photographers. They then recruited 89 adult participants and 77 child participants and categorized them according to their age, the dog-positivity of their cultural context, and the participants’ personal history of dog ownership.

Each participant was presented with photographs of dogs, chimps, and humans, and asked to rate how much the individual in the picture displayed happiness, sadness, anger, or fear. Adults were also asked to determine the context in which the picture had been taken (e.g., playing with a trusted conspecific partner; directly before attacking a conspecific). The results of the study showed that, while some dog emotions can be recognized from early on, the ability to reliably recognize dog emotions is mainly acquired through age and experience. In adults, the probability of recognizing dog emotions was higher for participants who grew up in a cultural context with a positive attitude towards dogs, regardless of whether they owned a dog themselves.

Without a dog-positive context, we could be barking up the wrong tree

A dog-postive cultural background, one in which dogs are closely integrated into human life and considered highly important, may result in a higher level of passive exposure and increased inclination and interest in dogs, making humans better at recognizing dogs’ emotions even without a history of personal dog ownership. “These results are noteworthy,” says Amici, “because they suggest that it is not necessarily direct experience with dogs that affects humans’ ability to recognize their emotions, but rather the cultural milieu in which humans develop.”

The researchers also found that regardless of age or experience with dogs, all participants were able to identify anger and happiness reliably. While these results may suggest an innate ability favored by the co-domestication hypothesis, it is also possible that humans learn to recognize these emotions quickly, even with limited exposure. Other than anger and happiness, the children in the study were not good at identifying dog emotions. They recognized anger and happiness more reliably in dogs than in chimps, but otherwise identified dog emotions as poorly as they did chimpanzee emotions, suggesting that the ability to understand how dogs are feeling is not innate.

“We think it would be valuable to conduct future studies that seek to determine exactly which cultural aspects affect one’s ability to read dog emotions, and to include real-life stimuli and body expressions in addition to instructed stimuli and facial expressions,” states Bräuer. “In this way, we could develop a better understanding of inter-cultural variation in emotion recognition. Hopefully this information could be used to reduce the occurrence of negative incidents between humans and dogs that are caused by humans’ inability to read dog signals.”

Source:  Max Planck Institute for the Science of Human History

 

Dogs are more expressive when someone is looking

Dogs produce more facial expressions when humans are looking at them, according to new research from the University of Portsmouth.

Scientists at the University’s Dog Cognition Centre are the first to find clear evidence dogs move their faces in direct response to human attention. Dogs don’t respond with more facial expressions upon seeing tasty food, suggesting that dogs produce facial expressions to communicate and not just because they are excited.

Brow raising, which makes the eyes look bigger – so-called puppy dog eyes – was the dogs’ most commonly used expression in this research.

Puppy dog eyes

Puppy dog eyes

Dog cognition expert Dr Juliane Kaminski led the study, which is published in Scientific Reports.

She said: “We can now be confident that the production of facial expressions made by dogs are dependent on the attention state of their audience and are not just a result of dogs being excited. In our study they produced far more expressions when someone was watching, but seeing food treats did not have the same effect.

“The findings appear to support evidence dogs are sensitive to humans’ attention and that expressions are potentially active attempts to communicate, not simple emotional displays.”KAMINSKI-dog-eyes

Most mammals produce facial expressions – such expressions are considered an important part of an animal’s behavioural repertoire – but it has long been assumed that animal facial expressions, including some human facial expressions, are involuntary and dependent on an individual’s emotional state rather than being flexible responses to the audience

Dr Kaminski said it’s possible dogs’ facial expressions have changed as part of the process of becoming domesticated.

The researchers studied 24 dogs of various breeds, aged one to 12. All were family pets. Each dog was tied by a lead a metre away from a person, and the dogs’ faces were filmed throughout a range of exchanges, from the person being oriented towards the dog, to being distracted and with her body turned away from the dog.

The dogs’ facial expressions were measured using DogFACS, an anatomically based coding system which gives a reliable and standardised measurement of facial changes linked to underlying muscle movement.

Co-author and facial expression expert Professor Bridget Waller said: “DogFACS captures movements from all the different muscles in the canine face, many of which are capable of producing very subtle and brief facial movements.

“FACS systems were originally developed for humans, but have since been modified for use with other animals such as primates and dogs.”

Dr Kaminski said: “Domestic dogs have a unique history – they have lived alongside humans for 30,000 years and during that time selection pressures seem to have acted on dogs’ ability to communicate with us.

“We knew domestic dogs paid attention to how attentive a human is – in a previous study we found, for example, that dogs stole food more often when the human’s eyes were closed or they had their back turned. In another study, we found dogs follow the gaze of a human if the human first establishes eye contact with the dog, so the dog knows the gaze-shift is directed at them.

“This study moves forward what we understand about dog cognition. We now know dogs make more facial expressions when the human is paying attention.”

It is impossible yet to say whether dogs’ behaviour in this and other studies is evidence dogs have flexible understanding of another individual’s perspective – that they truly understand another individual’s mental state – or if their behaviour is hardwired, or even a learned response to seeing the face or eyes of another individual.

Puppy dog eyes is a facial expression which, in humans, closely resembles sadness. This potentially makes humans more empathetic towards the dog who uses the expression, or because it makes the dog’s eyes appear bigger and more infant-like – potentially tapping into humans’ preference for child-like characteristics. Regardless of the mechanism, humans are particularly responsive to that expression in dogs.

Previous research has shown some apes can also modify their facial expressions depending on their audience, but until now, dogs’ abilities to do use facial expression to communicate with humans hadn’t been systematically examined.

Source:   University of Portsmouth news

Link to publication

Happy faces/sad faces

This is the experimental set-up used to test whether dogs can discriminate emotional expressions of human faces.  Photo by Anjuli Barber, Messerli Research Institute

This is the experimental set-up used to test whether dogs can discriminate emotional expressions of human faces. Photo by Anjuli Barber, Messerli Research Institute

Dogs can tell the difference between happy and angry human faces, according to a research published recently in the journal Cell Biology.

The discovery represents the first solid evidence that an animal other than humans can discriminate between emotional expressions in another species, the researchers say.

Previous attempts had been made to test whether dogs could discriminate between human emotional expressions, but none of them had been completely convincing. In the new study, the researchers trained dogs to discriminate between images of the same person making either a happy or an angry face. In every case, the dogs were shown only the upper or the lower half of the face. After training on 15 picture pairs, the dogs’ discriminatory abilities were tested in four types of trials, including (1) the same half of the faces as in the training but of novel faces, (2) the other half of the faces used in training, (3) the other half of novel faces, and (4) the left half of the faces used in training.

The dogs were able to select the angry or happy face more often than would be expected by random chance in every case, the study found. The findings show that not only could the dogs learn to identify facial expressions, but they were also able to transfer what they learned in training to new cues.

“Our study demonstrates that dogs can distinguish angry and happy expressions in humans, they can tell that these two expressions have different meanings, and they can do this not only for people they know well, but even for faces they have never seen before,” says Ludwig Huber, senior author and head of the group at the University of Veterinary Medicine Vienna’s Messerli Research Institute.

This research adds to the body of knowledge about the human-animal bond.  The researchers believe it is likely that the dogs associate a smile with a positive meaning and an angry expression with a negative one.

Source:  EurekAlert! media release