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. 2015 Oct 7:5:15021.
doi: 10.1038/srep15021.

Tolerance and reward equity predict cooperation in ravens (Corvus corax)

Jorg J M Massen  1 , Caroline Ritter  1 , Thomas Bugnyar  1   2
Affiliations

Tolerance and reward equity predict cooperation in ravens (Corvus corax)

Jorg J M Massen et al. Sci Rep. .

Abstract

Cooperative decision rules have so far been shown experimentally mainly in mammal species that have variable and complex social networks. However, these traits should not necessarily be restricted to mammals. Therefore, we tested cooperative problem solving in ravens. We showed that, without training, nine ravens spontaneously cooperated in a loose-string task. Corroborating findings in several species, ravens' cooperative success increased with increasing inter-individual tolerance levels. Importantly, we found this in both a forced dyadic setting, and in a group setting where individuals had an open choice to cooperate with whomever. The ravens, moreover, also paid attention to the resulting reward distribution and ceased cooperation when being cheated upon. Nevertheless, the ravens did not seem to pay attention to the behavior of their partners while cooperating, and future research should reveal whether this is task specific or a general pattern. Given their natural propensity to cooperate and the results we present here, we consider ravens as an interesting model species to study the evolution of, and the mechanisms underlying cooperation.

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Figures

Figure 1
Figure 1. Experimental set-up.
Two birds have to pull the two ends of the string simultaneously to move the feeding platform in reach. If only one bird pulls, the string will just go through the two metal loops anchored to the feeding platform and become unthreaded, while the platform remains stationary. Picture drawn by Nadja Kavcik-Graumann.
Figure 2
Figure 2
(a) Mean inter-individual tolerance score per dyad (see ESM) and its relation to cooperative success in the group setting (study 1), and (b) mean inter-individual tolerance score per dyad (see ESM) and its relation to cooperative success in the dyadic setting (study 2). Solid lines reflect trend-lines and dashed lines indicate the 95% confidence intervals.
Figure 3
Figure 3
(a) Proportion of trials in which two birds cooperated successfully subsequent to an equal or unequal reward devision after the previous successful cooperation trial, and (b) proportion of trials in which a bird pulled the string after it had received zero, one or two rewards in the previous successful cooperation trial.
See this image and copyright information in PMC

References

    1. Moll H. & Tomasello M. Cooperation and human cognition: the Vygotskian intelligence hypothesis. Phil. Trans. R. Soc. B 362, 639–648 (2007). - PMC - PubMed
    1. Rand D. G. & Nowak M. A. Human cooperation. TICS 17, 413–425 (2013). - PubMed
    1. Carleton W. M. Mind in Society - the Development of Higher Psychological Processes - Vygotsky, Ls. Q. J. Speech 66, 224–225 (1980).
    1. Boyd R. The puzzle of human sociality. Science 314, 1555–1556 (2006). - PubMed
    1. Seed A. M., Clayton N. S. & Emery N. J. Cooperative problem solving in rooks (Corvus frugilegus). Proc. R. Soc. B. 275, 1421–1429 (2008). - PMC - PubMed

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