Behavioral Responses to Inequity in Reward Distribution and Working Effort in Crows and Ravens

• DOI: 10.1371/journal.pone.0056885
• Publication Date: 2013-02-20T17:49:21Z
• Authors: Claudia A. F. Was...; Thomas Bugnyar
• Keywords: Inequity aversion; Equity; Social Preferences

Sensitivity to inequity is considered be a crucial cognitive tool in the evolution of human cooperation. The ability has recently been shown also primates and dogs, raising question an evolutionary basis aversion. We present first evidence that two bird species are sensitive other individuals' efforts payoffs. In token exchange task we tested both behavioral responses quality reward (preferred versus non-preferred food) absence presence rewarded partner, 5 pairs corvids (6 crows, 4 ravens). Birds decreased their performance when experimental partner received as gift, which indicates they working effort. They compared with equity condition. Notably, refused take after successful more often conditions. Our findings indicate awareness payoffs may evolve independently phylogeny systems given degree social complexity.