To the list of the qualities of dogs — enthusiastic and steadfast come to mind — can be added another. That pooch of yours, researchers say, may be envious.
Scientists in Austria report in The Proceedings of the National Academy of Sciences that a dog may stop obeying a command if it sees that another dog is getting a better deal.
In this way dogs may be showing a sensitivity that is similar to, although perhaps more primitive than, that shown by chimpanzees and some monkeys. Until now those primates were the only nonhumans to show what is called “inequity aversion” in the absence of a reward.
The finding may come as no surprise to some dog owners, and it didn’t completely surprise Friederike Range, a postdoctoral researcher at the University of Vienna who led the study.
“We have a dog at home,” she said, “and I know how jealous she is of different people and situations.”
The study tried to quantify the behavior by using well-trained dogs that readily offer a paw on command. The researchers used two dogs side by side but treated them differently, giving one a better reward (sausage) and the other a lesser one (bread) when the paw was given, or giving one dog no reward at all.
They found that the quality of the reward made little difference. But in the case in which one dog got no treat at all, that dog became less and less inclined to obey the command.