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

Massen JJ, Ritter C, Bugnyar T - Sci Rep (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: University of Vienna, Department of Cognitive Biology, Vienna, Austria.

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.

No MeSH data available.


(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.
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f2: (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.

Mentions: The ravens cooperated successfully in 397 out of 600 trials (66.17%). Every individual was successful in at least 32 trials, yet there was quite some variation in how successful they were with all possible partners, and 3 out of 21 possible dyads never cooperated successfully with each other. To test what possible factors might explain the difference in success between the different dyads, we ran a generalized linear mixed model (GLMM) on the number of successful cooperation trials, in which we added inter-individual tolerance levels, dominance rank, rank distance, sex, sex-combination and kinship (yes/no) as fixed effects, and the identity of the dyad and the subject of analyses as random effects to control for repeated measurements. We found that inter-individual tolerance was the only significant predictor of successful cooperation (β = 1.810, F = 13.2, d.f.n. = 1, d.f.d. = 34, P = 0.001), suggesting that cooperative success increases with increasing inter-individual tolerance (Fig. 2a) (see electronic supplementary materials for best fitting model).


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

Massen JJ, Ritter C, Bugnyar T - Sci Rep (2015)

(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.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595729&req=5

f2: (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.
Mentions: The ravens cooperated successfully in 397 out of 600 trials (66.17%). Every individual was successful in at least 32 trials, yet there was quite some variation in how successful they were with all possible partners, and 3 out of 21 possible dyads never cooperated successfully with each other. To test what possible factors might explain the difference in success between the different dyads, we ran a generalized linear mixed model (GLMM) on the number of successful cooperation trials, in which we added inter-individual tolerance levels, dominance rank, rank distance, sex, sex-combination and kinship (yes/no) as fixed effects, and the identity of the dyad and the subject of analyses as random effects to control for repeated measurements. We found that inter-individual tolerance was the only significant predictor of successful cooperation (β = 1.810, F = 13.2, d.f.n. = 1, d.f.d. = 34, P = 0.001), suggesting that cooperative success increases with increasing inter-individual tolerance (Fig. 2a) (see electronic supplementary materials for best fitting model).

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: University of Vienna, Department of Cognitive Biology, Vienna, Austria.

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.

No MeSH data available.