Just a few short years after scientists conclusively proved that dogs have unique personalities–something that every dog lover already knew–a new study has shown that canine temperament is more nuanced than many people suspected.

NPR reported yesterday on a new study that shows dogs have a sense of fairness and experience jealousy. Here is a quote from the story.

Friederike Range, a researcher at the University of Vienna in Austria, and her colleagues did a series of experiments with dogs who knew how to respond to the command “give the paw,” or shake. The dogs were normally happy to repeatedly give the paw, whether they got a reward or not.

But that changed if they saw that another dog was being rewarded with a piece of food, while they received nothing.

“We found that the dogs hesitated significantly longer when obeying the command to give the paw,” the researchers write. The unrewarded dogs eventually stopped cooperating.

Frans de Waal, a scientist at Emory University, was not surprised by the findings. He and colleagues performed research that demonstrated jealousy and a sense of fairness in monkeys.

Dogs, like monkeys, live in cooperative societies, so de Waal was not surprised that they would have also some sense of fairness. He expects other animals do as well. For example, he says, lions hunt cooperatively, and he “would predict that lions would be sensitive to who has done what and what do they get for it.”

The emotional lives of animals are very poorly understood by humans. But it is clear that animal emotions are much more complex than many people had formerly believed.

Thank you to Elizabeth of Washington, DC for alerting me to the article.

Photo: Skye King is ready to shake, treat or no treat.