Do dogs read our faces?

Research by the University of Lincoln suggests dogs may read human faces in the same way people do.

A multi-disciplinary team has found evidence to suggest that pet dogs may use a trait known as ‘left gaze bias’ to pick up clues about their master’s mood.

It is thought the same ploy is used subconsciously by humans to quickly assess other people’s faces.

Tests have indicated that the right hand side of the human face is better at expressing the nuances of emotion – particularly anger.

One hypothesis is that our eyes naturally wander to this side of the face when we look directly at people in order to pick up these clues.

The research team, led by Professor Daniel Mills, Dr Kun Guo and Dr Kerstin Meints, discovered that domestic dogs appear to use the same tactic to judge their master’s mood.

Dr Kun GuoDr Kun Guo, Senior Lecturer in Psychology at the University of Lincoln, said: “We found that a dog looks at a human face in the same way that we look at a human face. It’s a trend known as left gaze bias. It could be that a dog uses this strategy to pick up human expressions and emotions. We were very surprised by our findings because in terms of a tree of evolution, dogs are very different to us. Somehow through social interaction dogs must have picked up some kind of cues from us in order to communicate with us.”

The research – a collaboration between the Psychology and Biological Sciences faculties – started in 2006.

Research students Sophie and Charlotte Hall, identical twins who are now studying PhDs in Psychology, worked on the initial project as research assistants.

Sophie Hall and HomerThe tests, which were conducted at the University’s Riseholme campus, involved taking dogs individually into a room with a large screen at one end.

The researchers then used a projector to present a series of different images onto the screen. These images included the faces of humans, dogs and monkeys, along with some inanimate objects.

Cameras controlled from an adjoining room recorded the dogs’ reactions. The team then conducted frame-by-frame analysis to record the animals’ eye movements.

In total, 17 dogs were involved in the research. The results appeared to show the dogs exhibited left gaze bias when looking at the human faces – but not when looking at the face of a dog or monkey, or when viewing an inanimate object.

Other than monkeys – known to be genetically similar to humans - no other animals are thought to show left gaze bias when looking at human faces.

The team believes dogs may have developed the strategy for reading human facial expressions over thousands of years of domestic co-existence.

PhD student Annaïs Racca is now working on further research into what information dogs can derive from human facial expressions.

Dr Guo said: “At the moment we are investigating the function of this bias – what kind of information can they pick up from a human face? We have strong evidence to suggest that dogs can use this strategy to detect anger.”

The initial research, which was published in New Scientist magazine and online in Animal Cognition, created great media interest.