Attribute to dogs a capacity to discriminate between just and unjust actions, and you’re likely to be accused of anthropomorphizing dogs, or worse. That’s still the general consensus in dog circles, owing largely to the influence of classical behaviorism. (Why it’s still so influential is another story, one I tell in my recently published book, Willing Dogs & Reluctant Masters.) Of course, observant and thoughtful dog owners have long known—often to their sorrow—that many dogs are not only capable of judging, but of making their verdicts scathingly clear.
Recent scientific experiments are confirming that dogs have a rudimentary sense of justice. Or, as the title of one study so eloquently puts it, “The absence of reward induces inequity aversion in dogs.” I quote from the abstract:
One crucial element for the evolution of cooperation may be the sensitivity to others’ efforts and payoffs compared with one’s own costs and gains. Inequity aversion is thought to be the driving force behind unselfish motivated punishment in humans constituting a powerful device for the enforcement of cooperation. Recent research indicates that non-human primates refuse to participate in cooperative problem-solving tasks if they witness a conspecific obtaining a more attractive reward for the same effort.
That’s putting it mildly. As is charmingly evident from this video, non-human primates do more than “refuse to participate”: they show a spirited anger in the face of the injustice.
But what about dogs? The abstract continues:
Here, we investigated whether domestic dogs show sensitivity toward the inequity of rewards received for giving the paw to an experimenter on command in pairs of dogs. We found differences in dogs tested without food reward in the presence of a rewarded partner compared with both a baseline condition (both partners rewarded) and an asocial control situation (no reward, no partner), indicating that the presence of a rewarded partner matters. Furthermore, we showed that it was not the presence of the second dog but the fact that the partner received the food that was responsible for the change in the subjects’ behavior. In contrast to primate studies, dogs did not react to differences in the quality of food or effort. Our results suggest that species other than primates show at least a primitive version of inequity aversion, which may be a precursor of a more sophisticated sensitivity to efforts and payoffs of joint interactions.
More specifically, they found that if you put several dogs together in a room and ask some dogs to “Shake!”, they were glad to do so, unless or until they happened to notice that other dogs near them were getting a treat for shaking, while they were not. This is just another version of the cucumber vs. the grape. Guess what happened next? The dogs treated unfairly began refusing to cooperate. So, next time you think your dog appears to be accusing you of injustice, well, they just might be!