Dog cognition expert Dr. Juliane Kaminski and colleagues investigated whether dog facial expressions can be subject to so-called audience effects.
The study involved 24 dogs (13 male and 11 female) of various breeds and ages (age range = 1–12 years). The dogs were normal family dogs with a training background typical for a pet dog.
Each dog was tied by a lead a meter 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 standardized measurement of facial changes linked to underlying muscle movement.
“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,” Dr. Kaminski said.
“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.”
Brow raising, which makes the eyes look bigger (so-called puppy dog eyes), was the dogs’ most commonly used expression in the study.
“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,” Dr. Kaminski said.
“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,” she said.
“It is impossible yet to say whether dogs’ behavior 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 behavior is hardwired, or even a learned response to seeing the face or eyes of another individual.”
The findings are published in the journal Scientific Reports.
Juliane Kaminski et al. 2017. Human attention affects facial expressions in domestic dogs. Scientific Reports 7, article number: 12914; doi: 10.1038/s41598-017-12781-x