An ‘unkindness’ of ravens? Measuring prosocial preferences in <em>Corvus corax</em> — ASN Events

An ‘unkindness’ of ravens? Measuring prosocial preferences in Corvus corax (#891)

Megan Lambert 1 , Jorg J.M Massen 2 , Amanda M Seed 3 , Thomas Bugnyar 2 , Katie E Slocombe 1
  1. Department of Psychology, University of York, York, United Kingdom
  2. Department of Cognitive Biology, University of Vienna, Vienna, Austria
  3. School of Psychology and Neuroscience, University of St. Andrews, Fife, United Kingdom

The nature and degree of humans’ prosocial, or ‘other-regarding’ behavior is a defining characteristic of our species, but its evolutionary origins are contentious. In recent years there has been considerable research effort aimed at testing prosocial tendencies in other species in controlled laboratory settings, however this has focused almost exclusively on non-human primates. Studies outside of the primate order can help uncover the socioecological factors that may favor prosocial behavior. Corvids (in particular, members of the genus Corvus)represent a promising group for such study as they are large-brained, socially complex birds that demonstrate primate-like cognitive abilities. Additionally, some corvid species such as ravens exhibit a range of cooperative behaviours including the formation of strong affiliative bonds characterized by frequent food sharing, preening and agonistic support. Using a revised method for measuring prosociality which disentangled motivation to provision a conspecific from motivation to feed next to one, we presented captive ravens (Corvus corax) with a low-cost prosocial choice task in which subjects received nothing for themselves, but could choose between a tray that delivered food to a conspecific or one that delivered food to an inaccessible, empty compartment. After first meeting criterion to ensure that they understood the experimental setup, each bird was tested with two different partners that varied in terms of their affiliation to the subject. Test trials were interspersed with motivation trials. Our results show that subjects often inhibited pulling on trials when they received nothing for themselves, and both the absolute number and proportion of subjects’ prosocial choices did not differ significantly from chance. The potential influence of the partner’s identity and behavior during trials is discussed. These preliminary results are consistent with studies of chimpanzees using comparable paradigms, and suggest that ravens do not act to benefit conspecifics in the absence of immediate self-gain.