Man's best friend expects a fair treat for doing tricks, canine cognitive scientists at the Clever Dog Lab in Austria report.
Like humans and chimpanzees, dogs seem to expect fairness in their dealings with humans. When two dogs sitting next to each other complete the same action — shaking paws in this case — but don't receive the same reward, the jilted dog stops playing along.
"I think it's an important finding because it goes beyond primates," said evolutionary biologist Marc Bekoff, author of a forthcoming book on animal morality, Wild Justice, who was not involved with the study. "It calls attention to the fact that animals are a heck of a lot smarter and more emotional than we give them credit for.
The new study, published this week in the Proceedings of the National Academy of Sciences, is part of a growing body of research showing that many social animals, including dogs, wolves and marmosets, have emotions previously considered unique to humans. While biologists have long thought that mammals experience primary emotions like fear, more recent studies have found strong evidence that a range of animals also feel more nuanced, secondary emotions like a sense of fairness.
"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," wrote Friederike Range and her colleagues from University of Vienna.
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To test this, the Austrian cognitive scientists placed two dogs side by side in front of a person. Both animals could clearly see a bowl filled with (delicious) sausage and dark bread treats. The animals were asked to "give the paw," generally known in American English as "shaking." The researchers then measured the amount of times (out of 30) that the animals gave the paw under various conditions.
In treat-heavy conditions, the dogs give their paws for nearly every trial. When neither dog was given rewards, the dogs only gave their paws 20 out of 30 times and they required more verbal prompting to do so. But, when one animal was rewarded and the other was not, the unrewarded dogs only shook 12 times and displayed considerably more agitation than in either of the other tests.
Bekoff said that social animals like the wolves and coyotes he has studied had to evolve the ability to read cues from other animals in order to display the levels of group cooperation that they do.
"I'm not at all surprised by this because I've spent years studying social carnivores," Bekoff said." The people who are surprised by this are the people who haven't spent as much time watching animals."
One such nonplussed scientist, Clive Wynne, a psychologist at the University of Florida, told the AP that he wasn't sure the experiment measured fairness at all.
"What it means is individuals are responding negatively to being treated less well," Wynne said.
But Bekoff took issue with Wynne's interpretation of the data.
"They are responding negatively to being treated to less well, but it also means they are picking up on what being treated less well means, and that's really important," Bekoff said. "The animals are aware of being treated less well."
With researchers discovering humanlike cognitive and emotional characteristics in all sorts of mammals, Bekoff said humans will have to come to terms with what makes us unique.
"In two areas, we're unique," he said. "We're the only species I know of that cooks food and [we have an] incredible propensity for evil."
