According to the new study, dogs are more likely to yawn when they hear only the sound of their owners yawning. The study said nearly half of all dogs yawned when they heard a recording of a human being making a yawning noise. But dogs were five times more likely to yawn if the sound of the yawning belonged to their owner.
Previous studies showed that dogs are among non-human animals that yawn. Other animals that yawn include macaques, baboons and chimpanzees. Live Science
reports that the phenomenon of contagious yawning is thought to indicate the ability to empathize with others and know or understand what they are feeling. A previous study at the University of London showed a link between ability to empathize and contagious yawning by demonstrating that autistic children do not "catch" yawns. This was taken as an indication that yawning is related to ability to empathize. Autism is a condition in which individuals show impaired social interaction and lack of empathy.
reports that a previous study had also shown that dogs can catch a yawn after watching a human being yawning. Live Science
reported a 2008 study by a psychologist at Birkbeck, University of London, involving dog breeds including Greyhound, Staffordshire Bull Terrier and Dalmatians. In the first scenario, a human, who was not the owner of the dog, yawned while keeping eye contact with the dog. In the second scenario, the human simply opened and closed his mouth without yawning.
It was found in the 2008 study that in the yawning session, 21 dogs, or 72 percent of the dogs, yawned while no dog yawned in the non-yawing scenario. The dogs' ability to "catch" a human yawn is compared to 45 percent to 65 percent found in studies in humans (humans-to-humans studies) and 33 percent found for chimpanzees(chimp-to-chimp studies).
The latest study to be published in the July 2012 edition of Animal Cognition
, was designed to test whether the phenomenon of contagious yawning between humans and dogs could be linked to empathy. Researchers reasoned that if dogs can catch a yawn from a human by simply listening to the recorded sound of a human yawning, without physically seeing the person, then it is likely that the phenomenon is an indication of empathy.
Lead researcher Karine Silva, behavioral biologist, said: "These results suggest that dogs have the capacity to empathize with humans." Science Now
reports that Silva explains that this should not be surprising. People first began domesticating dogs at least 15,000 years ago and have bred them for ability to socialize with humans.
In the study conducted at the University of Porto in Portugal, 29 dogs that had lived with their owners for at least 6 months were played recordings of the owners yawning, yawns of an unfamiliar woman and a control sound. The control sound was the noise of a yawn played backwards.
The dogs were tested using the recorded sounds in two sessions, one week apart, and the number of yawns from each noise was recorded. The results showed that dogs were more likely to yawn when they heard the yawn of their owners than the yawn of a stranger or when a yawn was played backwards.
According to Huffington Post
, Evan McLean, a Ph.D student at Duke University's Canine Cognition Center in Durham, North Carolina, said: "This study tells us something new about the mechanisms underlying contagious yawning in dogs. As in humans, dogs can catch this behavior using their ears alone."
reports that Adam Miklosi, an ethologist at the Eotvos Lorand University in Budapest, expressed skepticism, saying that previous studies showed dogs looked guilty even when they were not. He said: "Using behaviors as indicators will only show some similarity in behaviour, but it will never tell us whether canine empathy, whatever this is, matches human empathy. Dogs can simulate very well different forms of social interest that could mislead people to think they are controlled by the same mental processes, but they may not always understand the complexity of human behaviour."
Scientists do not yet have a full explanation of the phenomenon of contagious yawning. Joly-Mascheroni
, who conducted the 2008 study, said: "There are theories that seem to think that we used to transfer this information of 'I am tired' by yawning when we didn't have language. It would be interesting to find out what other information we transfer to dogs or to any other animals that we are not aware of."