Next time your dog gets rowdy when you start cuddling your friend's puppy, you'll know what's up. A research team from the University of California, San Diego discovered that Fang might experience jealousy, though not quite like you and I do.
UC San Diego psychologist Christine Harris has been studying human jealousy for years. She became curious about the possibility of jealousy in dogs when she noticed her two border collies fought for her attention when she gave it to just one. Researchers are split on whether dogs are capable of experiencing true emotions, because they aren't capable of higher-level thinking, so Harris went about evaluating canine jealousy similarly to how the emotion is tested in another less-cerebral group: human babies.
Harris and her team collected dogs and their owners and had them engage in two activities. First, dog owners were asked to pet and talk to realistic stuffed dogs that made noises while their own dogs looked on. According to the New York Times, this behavior got a rise out of the real dogs, which barked and pushed the stuffed dogs out of the way.
However, the second activity didn't elicit as much of a reaction. After playing with fake dogs, dog owners read books to and petted jack-o'-lanterns to see if dogs became envious of any and all attention. Turns out they don't. In her recent paper published in PLOS ONE, Harris concluded that "jealousy has some 'primordial' form that exists in human infants and in at least one other social species besides humans."
What occured might look a lot like jealousy, but there's a reason Harris hedges in her conclusion. The test confirms that a lack of attention in the presence of some elicits a reaction, but it doesn't prove genuine jealousy. What it does show is that if attention is being given out, your dog wants it—especially if a rival is on the receiving end.
Tests like this, researchers told the Times, could support the idea that emotions such as jealousy are innate across species—and could inform whether we should seek to eliminate it or learn to manage it better.