Cognitive tools and emotional context in the development of canine coo

Research Blog, 09.12.2008, Friederike Range

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One crucial element for the evolution of cooperation may be the sensitivity to others' efforts and pay-offs in comparison to 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 witnessing a conspecific obtaining a more attractive reward for the same effort. However, little is known about non-primate species although inequity aversion may also be expected in other cooperative species.

Here, we investigated whether domestic dogs show sensitivity towards 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 to 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' behaviour.

In contrast to primate studies, dogs did not react to differences in the quality of food or effort.

Our results suggest that other species than primates show at least a primitive version of inequity aversion, which may be a precursor of a more sophisticated sensitivity to efforts and pay-offs of joint interactions.

The article is publised this week online in the Journal Proceedings of the National Akademy of Science:
Range, F., Horn, L., Viranyi, Zs. & Huber, L (in press) Effort and reward: Inequity aversion in domestic dogs? PNAS