Dogs Catch Yawns, But Young Puppies Can’t
Lawrence LeBlond for redOrbit.com – Your Universe Online
Yawns are contagious, but only for some! Previous research has found that man´s best friend is able to catch yawns from its owner. New research has taken the study a step further, showing that while dogs can catch yawns from humans, young puppies do not have the ability to do so.
The new study found that, although dogs are vulnerable to contagious yawning, those under the age of seven months are immune to the yawn contagion. The evidence indicates that a dog´s sense of empathy develops as it matures.
Previous assumptions of contagious yawning held that it was a sign of boredom or sleepiness. But researchers now know it is actually an empathetic trait, and has been witnessed in humans, adult chimpanzees, baboons and dogs. Most forms of empathy, the mimicking of emotional responses of others, are difficult to measure directly. However, researchers have been able to measure empathy through contagious yawning fairly easily.
Research into contagious yawning has been done extensively in human children, but this is the first study to investigate its development in another species´ young.
Led by Elainie AlenkÃ¦r Madsen and Tomas Persson of Sweden´s Lund University, researchers incorporated 35 Danish dogs between 4 and 14 months old into their study.
For the study, researchers observed the dogs´ responses when a human repeatedly yawned or gaped, or performed neither of the expressions. They found that only dogs over seven months of age yawned in response of the human trigger.
The pattern mirrors that seen in humans, who also become more vulnerable to the contagion as they mature; In human children, the mimicking behavior begins at around age four. This is the age when a number of related cognitive abilities, including empathy, begin to manifest clearly.
The findings suggest this is a general development pattern so far only known in humans, some primates and dogs. Given that contagious yawning may be an empathetic response, the results suggest that empathy and the mimicry that may underlie it develop slowly over the first year of a dog´s life.
Also, the findings indicate that empathy and mimicry development is a relatively gradual process, with researchers noting that yawn response in younger dogs is delayed compared to that of older dogs; it took longer to evoke contagious yawning in young dogs compared to adult dogs tested previously using the same general method. Furthermore, the contagious yawning response in adult dogs is more accurate than in puppies, as the youngest yawners do so by merely seeing someone´s jaws gape.
The researchers also found some evidence that the emotion of yawning often transferred to sleepiness in the dogs, as nearly half of the puppies that responded to yawning, became less aroused, and fell into slumber.
Previous studies suggest that individuals, be it dogs or humans, are more likely to yawn contagiously to those with whom they have close emotional bonds. However, this research team tested the dogs with both an unfamiliar subject and with their owner, and found no evidence that the puppies preferentially yawned in response to the yawns of the human with whom they were emotionally bonded to.
Since this has also been the case in young human children, the team suggests that in species that show empathy, the emotional bond effect only emerges later on in development
The research will be published in the November issue of the journal Animal Cognition.