In another case of science catching up with common sense, researchers have found that it is possible to make dogs jealous: they snap and bark more often when their owners engage with what appears to be another dog.
As always with studies like this, the methodology is pretty hilarious. It's adapted for a test used for 6-month-old human babies. The researchers went to the homes of 36 dogs, where they asked the dogs' owners to shower affection on a robotic stuffed dog, which barked and wagged its tail, while ignoring their actual dog. Owners were also asked to pay similar attention to a plastic jack-o-lantern pail, to interact with it as though it were a real dog. And finally, they were asked to read aloud a children's book. Two raters coded the video of these interactions for instances of aggression.
Why use the jack-o-lantern and children's book? Well, the researchers wanted to distinguish between the ways dogs behaved when they were being ignored, versus behaviors that might arise because of the loss of affection due to an interloper.
The dogs, perhaps predictably, were not having the pretend dog: they were twice as likely to push or touch their owners when the owner was paying attention to the robodog than when the owner was playing with the jack-o-latern pail; 78 percent of the dogs displayed pushing and touching in response to the fake dog. By contrast, 42 percent did this with the jack-o-latern, and only 22 percent did it when the owner read the book.
A third of dogs tried to place their bodies between their owners and the robot dog, the sweet dummies. A quarter of them snapped at the "other dog," but only one dog snapped at the obviously inanimate objects.
Perhaps fortunately, dogs can't talk. So how did the researchers know whether their robo-Fido fooled the actual dogs? Well, about 86 percent of the real dogs attempted to say hello to the fake dogs by sniffing their rears during or after the experiment.
Why bother with the experiment at all? Well, there's some argument among researchers about whether jealousy is innate, or an exclusively-human, learned emotion. The results of this admittedly silly test suggest that there may be some biological underpinnings for jealousy among social animals. Such "primordial" jealousy is displayed by infants as young as 6 months old. But if jealousy has a functional form, it should occur among other social species, where emotional bonds provide protection. Even Charles Darwin has suggested that jealousy exists in other species -- including dogs.
It's possible jealousy might derive from competing for parental resources -- by preventing your parents from forming a stronger bond with your other siblings, you might be rewarded with more attention or food. Another possibility is that jealousy evolved to keep pair-bonded sexual partners; little is known about the difference between romantic jealousy versus its more prosaic cousin. But the study does provide evidence that animals also experience jealousy: You shall play fetch with no other dog; for your DOG, whose name is Jealous, is a jealous dog.
