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Social influences on delayed gratification in New Caledonian crows and Eurasian jays.

Published version
Peer-reviewed

Repository DOI


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Authors

Davies, James R 
Schiestl, Martina 
Garcia-Pelegrin, Elias 
Gray, Russell D 

Abstract

Self-control underlies goal-directed behaviour in humans and other animals. Delayed gratification - a measure of self-control - requires the ability to tolerate delays and/or invest more effort to obtain a reward of higher value over one of lower value, such as food or mates. Social context, in particular, the presence of competitors, may influence delayed gratification. We adapted the 'rotating-tray' paradigm, where subjects need to forgo an immediate, lower-quality (i.e. less preferred) reward for a delayed, higher-quality (i.e. more preferred) one, to test social influences on delayed gratification in two corvid species: New Caledonian crows and Eurasian jays. We compared choices for immediate vs. delayed rewards while alone, in the presence of a competitive conspecific and in the presence of a non-competitive conspecific. We predicted that, given the increased risk of losing a reward with a competitor present, both species would similarly, flexibly alter their choices in the presence of a conspecific compared to when alone. We found that species differed: jays were more likely to select the immediate, less preferred reward than the crows. We also found that jays were more likely to select the immediate, less preferred reward when a competitor or non-competitor was present than when alone, or when a competitor was present compared to a non-competitor, while the crows selected the delayed, highly preferred reward irrespective of social presence. We discuss our findings in relation to species differences in socio-ecological factors related to adult sociality and food-caching (storing). New Caledonian crows are more socially tolerant and moderate cachers, while Eurasian jays are highly territorial and intense cachers that may have evolved under the social context of cache pilfering and cache protection strategies. Therefore, flexibility (or inflexibility) in delay of gratification under different social contexts may relate to the species' social tolerance and related risk of competition.

Description

Acknowledgements: Thank you to Ian Millar for help in apparatus construction and to Alizée Vernouillet for assisting in initial related training of Eurasian jays. Thanks to Province Sud for the permission to work in New Caledonia, and to Dean M. and Boris C. for granting property access for catching and releasing the crows.


Funder: FP7 Ideas: European Research Council; funder-id: http://dx.doi.org/10.13039/100011199; Grant(s): 3399933


Funder: Royal Society of New Zealand Rutherford Discovery Fellowship


Funder: Prime Minister’s McDiarmid Emerging Scientist Prize

Keywords

Animals, Adult, Humans, Crows, Delay Discounting, Feeding Behavior, Songbirds, Passeriformes, Reward

Journal Title

PLoS One

Conference Name

Journal ISSN

1932-6203
1932-6203

Volume Title

18

Publisher

Public Library of Science (PLoS)
Sponsorship
Anglia Ruskin University (Research Support Development Grant and Biology QR funds)