Cooperation in corvids and the evolution of cognition.
- Jorg J.M. Massen, Department of Cognitive Biology, University of Vienna, Austria.
- Wednesday 21 December 2016
- Faculty of Social Sciences
2333 AK LEIDEN
The social intelligence hypothesis argues that large brains have evolved in parallel with an increased complexity in the social environment, since maneuvering successfully through such a complex social world requires advanced socio-cognitive skills, like for example cooperation. While this hypothesis could theoretically be applied to any given species or taxon, such advanced socio-cognitive skills have so far mainly been tested in non-human primates, most notably in apes. However, to truly test the influence of social complexity on socio-cognitive skills and required brain size, we need to exclude confounding effects of common ancestry, ideally by also testing animals outside our own phylogenetic lineage. Among birds, corvids are known for their large relative brain size, and recent studies are slowly uncovering the complexity of their social environment. Raven flocks, for example, show high fission-fusion dynamics, much like for example chimpanzee groups. The results of a series of our experiments revealed that the cooperative skills of ravens are in fact also comparable to those of chimpanzees. However, whereas prosociality is regarded as one of the possible proximate motivations for cooperation, ravens’ prosocial tendencies are relatively low to non-existent. In contrast, some of our most recent work on azure-winged magpies shows that this cooperatively breeding corvid does behave prosocially towards group members. By comparing corvids with different breeding styles, we test an extension to the social brain hypothesis that also originates from primatology; namely, that cooperative breeding leads to more inter-individual tolerance and to the evolution of extreme prosocial tendencies, such as those observed in humans. Consequently, I would like to argue that to test evolutionary hypotheses about the evolution of intelligence, we need comparative work that also encompasses species of different orders or even classes.