AUDIE CORNISH, HOST:
Earlier this week, we saw a small headline with eye-popping relevance to some of our lives - scientists find jealousy in dogs. Now, that headline may overplay the findings a bit. In order to peer behind it, we got in touch with Christine Harris. She is a psychologist at the University of California San Diego and she performed the study, which was published in the journal "Plos One." Dr. Harris told us the idea emerged when she was studying jealousy in human relationships.
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CHRISTINE HARRIS: And at that time, I was visiting my parents, who had three border Collie's, and I noticed that when I was paying attention to two of them, it wouldn't of been surprising if the third one wanted attention - but what was interesting is that the two dogs I would be petting and looking at wouldn't want to share my affection and attention. One would bump the other one out of the way or knock his head out of the way and it fits with this one theory of jealousy that it evolved in order to protect important interpersonal relationships. So jealousy requires a triangle - the self, the loved one and the rival. And what I think the core motivation is to get in between the loved one and the rival. And it speaks to theories that jealousy is fundamentally a human emotion. However, we're not the only social species can have relationships threatened by others. Dogs bond with others, those relationships can be threatened and they're cognitively quite sophisticated. So if you're going to see jealousy in another species it would likely be the dog.
CORNISH: So in the study you filmed animals, dogs reacting to their owners playing with various objects. Talk about those objects and how the dogs reacted.
HARRIS: The owners either read a book out loud or they petted and paid attention to a stuffed dog like it was real or they did the same behaviors toward a jack-o'-lantern. We videotaped the real dogs reactions and the real dogs showed behaviors that could be indicative of jealousy when their owners paid attention to the stuffed dog. They tried to get between their owner they touched and nudged their owner more and they showed a 25 percent of them showed aggression toward the object. We saw very little of this when the book was the object the owner was paying attention and somewhere in between was the jack-o'-lantern.
CORNISH: Now, definitive can a study like this be? I mean you're simply observing a dog's behavior but do you really know that it's jealousy?
HARRIS: We don't know what the dog is feeling. What we are looking at are behaviors that would look like they were indicative of a motivational state of jealousy. And because of the tight control of the study, we do know that the behaviors were different across these three conditions so it's not simply the loss of attention but I also do not want to oversell the study. It's one finding - I think there are many places we could go to do some additional tighter controls - to try to understand more about this.
CORNISH: Christine Harris, help us understand what's the value of this in terms of understanding human emotions.
HARRIS: With human emotions, especially in the case of jealousy, we didn't know what the origin of it is. It could be social construction. It could be hardwired. If you see behaviors that resemble jealousy in humans in another species it helps give us a clue that maybe jealousy is hardwired in humans or at least has some aspect of it that is hardwired.
CORNISH: Before I let you go, I got to ask if your dog person.
HARRIS: I'm a dog person but I don't currently own a dog. I currently own a cat.
CORNISH: That means your cat person.
HARRIS: (Laughing) I'm not. I'm one of those people who loves them both equally.
CORNISH: All right, Doctor Christine Harris at the University of California San Diego, part of a team that set out to determine if dogs can feel jealousy. Thanks so much for speaking with us.
HARRIS: Thank you. Transcript provided by NPR, Copyright NPR.