The Joint Log-Lift Task: A Social Foraging Paradigm.

Jean-Loup Rault,Roger Mundry,Irene Camerlink,Marek Špinka,Sébastien Goumon

doi:10.3389/fvets.2021.745627

Abstract

Behavioural cooperation is under intense research. Yet, popular experimental paradigms often employ artificial tasks, require training, or do not permit partner choice, possibly limiting their biological relevance. We developed the joint log-lift task, a social foraging paradigm in which animals have to jointly lift a log to each obtain a food reward. The task relies on an obligate strategy, meaning that the only way to benefit is to work jointly. We hypothesised that (1) animals learn to spontaneously solve the task, and that (2) kin and (3) more sociable individuals would engage more often together in the task and achieve greater success than non-kin and less sociable individuals, respectively. We presented the task to 8 groups of juvenile domestic pigs (Sus scrofa domesticus) in their home pen for 30 min daily. Over the course of 9 days, the pigs showed evidence of learning by progressively switching from individual to joint behaviours, leading to 68% (62 out of 91 pigs) spontaneously solving the task. Success was influenced by sociability, but not kinship. There were large differences in success among dyads, hinting at the possible role of social dynamics and inter-individual differences in the ability and/or motivation to solve the task. The joint log-lift task allows researchers to investigate spontaneous cooperative tendencies of individuals, dyads and groups in the home environment through ad libitum engagement with the apparatus. This ecologically relevant paradigm opens the way to investigate social foraging experimentally at large scale, by giving animals free choice about when and with whom to work jointly.

Highlights

Cooperation, a behavioural strategy in which agents achieve a common goal through coordinated action [1], has been investigated in a variety of animal species ranging from mammals [2,3,4,5] and birds [6] to social arthropods [7,8,9]
We developed the joint log-lift task (JLLT), in which two animals have to jointly lift a log to each obtain a food reward
Pigs solved the JLLT spontaneously, progressively switching from individual to joint behaviours, with almost half of the pigs being successful on the last day and two thirds of the pigs having succeeded at least once over the course of the 9 days

Summary

Introduction

Cooperation, a behavioural strategy in which agents achieve a common goal through coordinated action [1], has been investigated in a variety of animal species ranging from mammals [2,3,4,5] and birds [6] to social arthropods [7,8,9]. Some experimental paradigms have been popular to investigate cooperation [reviewed in [10]], such as the “string pulling task” (or “loose-string paradigm”) employed in more than 160 bird and mammal species [11]. Such approaches have provided insightful knowledge on the socio-cognitive abilities of various species. Support is growing to investigate cooperation across animal species using ecologically-relevant contexts and species-specific paradigms [10]

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Discussion

Conclusion