This originally appeared in Psychology Today.
While most people accept that domestic dogs and other nonhuman animals (animals) experience basic emotions such as anger, fear, anxiety, joy, happiness, grief, and sadness, some doubt whether dogs are cognitively sophisticated enough to display jealousy, guilt, shame, or embarrassment, the so-called "higher" or "more complex" emotions. However, existing data do not support the claim that they don't.
A new study by Christine Harris and Caroline Prouvost working at the University of California in San Diego called "Jealousy in Dogs" published in the open-access journal PLOS ONE, shows that dogs experience what we call jealousy in humans. This research is also covered here and here. The abstract for this study reads as follows:
It is commonly assumed that jealousy is unique to humans, partially because of the complex cognitions often involved in this emotion. However, from a functional perspective, one might expect that an emotion that evolved to protect social bonds from interlopers might exist in other social species, particularly one as cognitively sophisticated as the dog. The current experiment adapted a paradigm from human infant studies to examine jealousy in domestic dogs. We found that dogs exhibited significantly more jealous behaviors (e.g., snapping, getting between the owner and object, pushing/touching the object/owner) when their owners displayed affectionate behaviors towards what appeared to be another dog as compared to nonsocial objects. These results lend support to the hypothesis that jealousy has some ‘‘primordial'' form that exists in human infants and in at least one other social species besides humans.