Making or breaking the case for a plain face – Is human perception of canine facial expressivity influenced by physical appearance?

Facial communication is important in both human-human interactions and human-dog interactions. Individual factors, such as experience, relationship history, and mood, to name a few, influence the reception of facial signals/expressions. But superficial facial features are also significant in human communication, and likely impact communication between dogs and humans. For example, humans are better at evaluating the frequency and intensity of facial expressions in dogs that have plainer faces, if the dog is familiar to them, which could be related to a preference for non-complexity (human faces are generally much less physically diverse than dog faces). This study explored the effect of the physical complexity of dog and human faces on the perceived expressiveness of neutral-faced, unknown individuals of both species. Results indicate that when looking at static images of unknown dogs and humans, facial complexity has minimal impact on how expressive people perceive them to be. However, dogs are consistently ranked as more expressive than humans, and people who live with dogs tend to rank neutral-face dogs of all facial complexity levels as more expressive compared to the rankings of humans who do not live with dogs – which we hypothesize may be the result of a desire/tendency of dog owners to “read meaning” into dog faces.