Discussions about human nature are usually characterized by efforts to determine which traits are unique to our species, thereby laying the foundations for a qualitative account of what it means to be human. As the body of research grows, more and more individual skills and behaviors, previously thought to be exceptionally human, are demonstrated to be representative of other animal species as well.
A new study, involving thirty six dogs and their owners, conducted by Christine R. Harris and Caroline Prouvost from the University of California San Diego, takes yet another trait off the table, this time – it‘s jealousy.
In humans, jealousy has far-reaching social and psychological consequences. For example, it is thought to be responsible for about 30% of premeditated homicides across cultures. While the exact origins and functions of jealousy are as yet unclear, most researchers agree that it can only arise within the context of a social triangle – that is, a situation where an interloper threatens a valued relationship. It is assumed that this much-maligned emotion increases evolutionary fitness by helping those who have a capacity for it to secure resources in a wide range of important affinities.
Although many dog lovers have reported their companions to exhibit jealous behaviors, up until now there has been no empirical evidence to support these claims. “The purpose of the study was to construct a social situation and determine whether dogs, whose owners show affection to a potential interloper, engage in behaviors indicative of jealousy.” – explain Harris and Prouvost.
To evaluate the subjects’ behavior, the research team modified a paradigm used to assess jealousy in 6-month-old infants. Thirty six dogs were videotaped and observed while their owners ignored them and interacted with three different types of objects. In the jealousy condition, the owners were asked to play with a stuffed dog while paying no attention to their own pet which was placed in the same room with them. In the second condition, the owners engaged in the same behaviors (petting, talking sweetly, etc.) towards a peculiar object (a jack-o-lantern). This allowed the researchers to determine whether the elicitation of jealousy requires the owners to show affection towards an appropriate stimulus or whether any object which directs attention away from the dog is enough to arouse jealous behaviors. In the third condition, the owners read a children’s book which had pop-up pages and played a melody. This was designed to determine whether the behaviors of dogs in other conditions were indicative of jealousy per se or whether they were more general negative affects arising due to the loss of the owner’s attention.
Results showed that the subject dogs acted much more aggressively when the owners interacted with the stuffed animal compared to when they engaged with the other objects. For example, 25% of the dogs snapped at the object in the jealousy condition but only 1 dog did so in the other two conditions.
Harris and Prouvost claim these findings indicate that jealousy does not require advanced cognitive capabilities and can exist in a primordial form: “… these findings add support to the view that jealousy can arise in the absence of complex interpretations of the meaning of the rival and loved one’s interaction and occurs in another species besides humans. We hope the current work will inspire further research into the social emotions of animals.”
Original research article: Jealousy in Dogs, Christine R. Harris, Caroline Prouvost | Published: July 23, 2014 | DOI: 10. 1371/journal.pone.0094597