By Roberta Attanasio
Dogs can be jealous — we’ve known this for a long time. However, these days, stories about the “surprising” finding of jealousy in dogs are all over the news, thanks to a research article (Jealousy in Dogs, July 23, 2014) published in the scientific journal PLOSone by Christine Harris and Caroline Prouvost (both at the University of California San Diego).
About a week ago, as a follow up to the publication of the article, you could read here and there: “Darwin was right”, “Darwin proven right”. Apparently, in The Descent of Man, Darwin wrote that a dog becomes jealous “of his master’s affection, if lavished on any other creature.” Despite the statement in the PLOSone article abstract that “It is commonly assumed that jealousy is unique to humans, partially because of the complex cognitions often involved in this emotion”, the finding of jealousy in dogs is not surprising to most dog owners, it is not surprising to avid Darwin’s readers, and it is not surprising to the scientific world either.
Indeed, it’s not the first time we hear from scientists about jealous dogs. Back in 2006, a study revealed that jilted dogs feel intense jealousy. Dr. Paul Morris, one of the researchers involved in the research, said at the time: “The study systematically investigated evidence for a wide range of emotions including jealousy, pride and guilt in a wide range of domestic animals. Our study provided good empirical evidence that has convinced many scientists that dogs at least demonstrate behaviour that is very like human jealousy.” The study was later published in the scientific journal Cognition and Emotion.
What’s so novel, then, about the findings of Harris and Prouvost? The findings are the result of “the first experimental test of jealous behaviors in dogs.”
Why did the researchers designed and carried out the experimental test? Harris told The Washington Post that she was visiting her parents and their three Border Collies when the idea for the study came to her. “I’d pet two of them at a time,” she said, “and it wouldn’t have been surprising if that had made the third want my attention, too.” But what intrigued her was that the two dogs being attended to would show aggression to one another. One dog would knock her hand away from the other, so it was the sole object of affection. “To me,” she said, “That really fit with the core motivation of jealousy.”
How did the researchers design the test? Because they could not find any previous experimental evidence of dog jealousy, Harris and Prouvost adapted a test used with 6-month-old human infants. They worked with 36 dogs in their own homes and videotaped the owners ignoring them in favor of a stuffed, animated dog or a jack-o-lantern pail. In both these conditions, the owners were instructed to treat the objects as though they were real dogs — petting them, talking to them sweetly, etc. In the third scenario, the owners were asked to read aloud a pop-up book that played melodies. Two independent raters then coded the videos for a variety of aggressive, disruptive and attention-seeking behaviors.
What did the researchers find? Dogs were about twice as likely to push or touch the owner when the owner was interacting with the faux dog (78 percent) as when the owner was attending to the pail (42 percent). Even fewer (22 percent) did this in the book condition. About 30 percent of the dogs also tried to get between their owner and the stuffed animal. And while 25 percent snapped at the “other dog,” only one did so at the pail and book.
What did the test results suggest? Harris said in a press release: “Our study suggests not only that dogs do engage in what appear to be jealous behaviors but also that they were seeking to break up the connection between the owner and a seeming rival,” In addition, Harris said. “We can’t really speak to the dogs’ subjective experiences, of course, but it looks as though they were motivated to protect an important social relationship.”
Did the dogs believe the stuffed animal was a real rival? Harris and Prouvost write that the aggressive behavior of the dogs suggests they did. The researchers also cite as additional evidence that 86 percent of the dogs sniffed the toy dog’s rear end during the experiment or post-experiment phase.
Did the study actually prove that dogs feel jealousy? Not really. Laurie Santos, director of the Canine Cognition Center at Yale University, told NPR: “The problem is that [the researchers] didn’t look at how dogs would react just to those objects.”
However, this is a landmark study that will drive future research to further understand the emotions of our pets and the evolutionary aspects of jealousy. In a 2008 Time article on “Covetous Canines“, Liz Logan wrote: “Emotions are a result of evolution: they cause organisms to act in ways that enable their survival. Jealousy, for instance, improves an animal’s chance of survival by motivating it to protect its mates and secure alliances for safety.”