If you have a dog you probably know that dogs yawn now and then. But did you ever notice that they yawn as a response to your yawning? In humans this phenomenon is well known as “contagious yawning”, but recent research indicates that even dogs can “catch” human yawns.

In 2008, Joly-Mascheroni et al. conducted a study1 investigating whether human yawns can elicit dog yawns. To test this, an experimenter was put in a room with a dog, the owner being behind the dog. For five minutes, the experimenter tried to make eye-contact with the dog and started yawning when eye-contact was established. This was repeated over and over again, causing most dogs to yawn at some point during this period. In the control condition, the procedure was similar, apart from the experimenter performing “non-yawning mouth opening actions”.

The results were the following: 21 out of 29 dogs yawned in the yawning session while no dogs yawned in between the sessions or during the control session. The dogs yawned after an average time of 1 minute and 39 seconds. This is strong evidence that contagious yawning also exists between humans and dogs.

The researchers note that their results allow for different interpretations. Previous research indicated that dogs yawn during stressful situations. In this case this would mean that the yawning session was somehow stressful for the dogs while the non-yawning session was not. The other interpretation is that contagious yawning between dogs and humans is empathy-mediated. This would be supported by the fact that more empathic people respond more strongly to other people’s yawns in experiments with humans, and by evidence that dogs are surprisingly good at understanding human social cues.

Some studies were performed afterwards yielding mixed results, supposedly due to varying methodology, such as using video-taped yawns. In 2013, Teresa Romero et al. conducted a study2 directly addressing the interpretation problem mentioned above. To address these issues, they had the owner and a stranger perform yawns to test whether owners can elicit more yawns, which would be expected by the empathy-interpretation. Furthermore they measured the heart rate of the dogs to assess whether the yawning-session was stressful to them.

Their protocol for yawning vs. non-yawning conditions was similar to Joly-Mascheroni et al. The results showed that significantly more yawns were observed with the owner yawning compared to a strange experimenter yawning. Furthermore the heart rate data demonstrated that the situation was not stressful for the animals. This strongly favors the empathy-mediated interpretation of contagious yawning between humans and dogs.

Because the research on this topic is still relatively young, the mechanisms involved aren’t yet understood. For example, Teresa Romero et. al. mention that the evolutionary origin of contagious yawning between humans and dogs is unknown. It is especially difficult to interpret why dogs show contagious yawning when together with humans but not when together with other dogs. Thus, further research is required to address such questions.

The abstract of “Dogs catch human yawn” paper:

This study is the first to demonstrate that human yawns are possibly contagious to domestic dogs (Canis familiaris). Twenty-nine dogs observed a human yawning or making control mouth movements. Twenty-one dogs yawned when they observed a human yawning, but control mouth movements did not elicit yawning from any of them. The presence of contagious yawning in dogs suggests that this phenomenon is not specific to primate species and may indicate that dogs possess the capacity for a rudimentary form of empathy. Since yawning is known to modulate the levels of arousal, yawn contagion may help coordinate dog–human interaction and communication. Understanding the mechanism as well as the function of contagious yawning between humans and dogs requires more detailed investigation.

Article written by Niclas Kuper

Sources

1 – Joly-Mascheroni RM, Senju A, Shepherd AJ

Dogs catch human yawn

Biology Letters

doi: 10.1098/rsbl.2008.0333

2 – Romero T, Konno A, Hasegawa T

Familiarity Bias and Physiological Responses in Contagious Yawning by Dogs Support Link to Empathy

PLoS ONE

doi:10.1371/journal.pone.0071365