Interesting psychology experiments 3: Contagious yawning works with dogs



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? This phenomenon is well known between humans as “contagious yawning”, but recent research indicates that even dogs can “catch” human yawns.

In 2008, Joly-Mascheroni et al. conducted a study investigating whether human yawns can elicit dog yawns. To test this, an experimenter was together 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 yawn-condition while no dogs yawned in between the sessions or during the control condition. The dogs yawned after a mean 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 condition was somehow stressful for the dogs while the non-yawning condition 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 study 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-condition 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 that dogs show contagious yawning together with humans but not together with other dogs. Thus, further research is required to address such questions.

I would be interested to know whether you can make your dog yawn by repeatedly yawning while making eye contact; I actually managed to do so. Please let me know in the comments.

This post is part of the blog post series “Interesting psychology experiments”.
See also:
Interesting psychology experiments 1: The marshmallow experiment
Interesting psychology experiments 2: Car crash study

Joly-Mascheroni RM, Senju A, Shepherd AJ (2008) Dogs catch human yawn. Biology Letters 4: 446–448. doi: 10.1098/rsbl.2008.0333

Romero T, Konno A, Hasegawa T (2013) Familiarity Bias and Physiological Responses in Contagious Yawning by Dogs Support Link to Empathy. PLoS ONE 8(8): e71365. doi:10.1371/journal.pone.0071365

Pigs can play video games

Dr Stanley Curtis of Penn State University conducted a study [1] in which he attempted to teach pigs to play a simple video game. The pigs had to move a joystick with their snouts in order to accomplish tasks with varying complexity such as moving a white dot into a blue area on the screen in front of them in order to receive a treat. The shape of the blue area became increasingly complex from experiment to experiment, but the pigs performed surprisingly well. They outperformed dogs by far and even performed better than chimpanzees.

See also: “5 surprisingly smart animals”

5 surprisingly smart animals

While it is sometimes assumed that only humans possess intelligence, there are some surprisingly smart animals in this world. Here are five of them:

photo_5101_20080227Pigeons:  Scientists found that pigeons are capable of remembering and discriminating between human faces. Furthermore they were able to use  their mirror image in an experiment – but only if they were previously trained to do so.[1] Mirror tests are frequently mentioned in relation to self-awareness, but it is unclear whether passing it is a sufficient criterion for self-awareness.


Dolphins:  Also Dolphins have passed the mirror test.  In one experiment, they looked at marks, previously made on their bodies, in a mirror.[2] Dolphins are able  to do various tricks such as jumping on comment and even to teach other, non-trained dolphins some of these tricks. It was discovered that dolphins sleep with only one half of their brain in order to remain alert with the other half. Thus they were capable of actively scanning their environment for 15 days in an experiment.[3]

rat-16927_640Rats: Rats were found to possess episodic-like memory: In an experiment they predicted where a preferred food pellet ( in this case chocolate – everybody loves chocolate!) would be. The place of the pellet depended on the length of the time interval previous to the beginning of the task. Rats were able to remember this from preceding experiments and searched in the appropriate locations. Plus, they can be trained to find their way through a complex maze – an ability that decreases with age due to memory impairment.[4]

octopus-250101_1280Octopuses: The number one expression of their intelligence is their ability to predict the outcome of important sports events – such as the world cup – with almost 100% accuracy. Just kidding. Octopuses were observed being able to use tools: In one experiment, an octopus used a coconut shell half as a shelter and carried it around afterwards.[5]  Also, they are famously known for escaping from the inside of closed jars.


Crows: Crows can use tools and naturally do so in the wild: One species uses tiny sticks in order to get insects out of little holes.[6]  Furthermore they are widely known for surprising problem solving abilities. Dr Alex Taylor tried to make a crow solve several different puzzles and when this was accomplished, he rearranged them in an order previously unknown to the crow, resulting in an almost incredible video of the crow perfectly solving all 8 puzzles. Video below:



Photo credit goes to: first 2 photographs freerange stock, last 3: pixabay