Abstract
For group-living animals to remain cohesive they must agree on where to travel. Theoretical models predict shared group decisions should be favoured, and a number of empirical examples support this. However, the behavioural mechanisms that underpin shared decision-making are not fully understood. Groups may achieve consensus of direction by active communication of individual preferences (i.e. voting), or by responding to each other's orientation and movement (i.e. copying). For example, African buffalo (Syncerus caffer) are reported to use body orientation to vote and indicate their preferred direction to achieve a consensus on travel direction, while golden shiners (Notemigonus crysoleucas) achieve consensus of direction by responding to the movement cues of their neighbours. Here, we present a conceptual model (supported by agent-based simulations) that allows us to distinguish patterns of motion that represent voting or copying. We test our model predictions using high-resolution GPS and magnetometer data collected from a herd of free-ranging goats (Capra aegagrus hircus) in the Namib Desert, Namibia. We find that decisions concerning travel direction were more consistent with individuals copying one another's motion and find no evidence to support the use of voting with body orientation. Our findings highlight the role of simple behavioural rules for collective decision-making by animal groups.
Highlights
For group-living animals to remain cohesive they must agree on where to travel
We find that decisions concerning travel direction were more consistent with individuals copying one another’s motion and find no evidence to support the use of voting with body orientation
Theoretical models predict that shared decision-making—where a majority of group members contribute to decisions—produces less extreme outcomes [2,4] and can result in greater decision accuracy [5,6,7] compared with unshared decisions dominated by an individual or minority of group members
Summary
For group-living animals to remain cohesive they must agree on where to travel. Theoretical models predict shared group decisions should be favoured, and a number of empirical examples support this. Hamadryas baboons (Papio hamadryas) and Tonkean macaques (Macaca tonkeana) are reported to use a similar voting mechanism—with individual body orientation indicating individuals’ preferred movement direction [11,18] These studies are consistent with the hypothesis that communication enables a type of structured decision-making whereby each group member is able to assess the relative support for different options among their group-mates [4]. Theoretical models and empirical data have demonstrated that individuals that do not have relevant prior information concerning the decision at hand can play an important role in consensus decision-making; enforcing equal representation of preferences and promoting a democratic outcome [19] Under this scenario, individuals copying each other’s movement (e.g. attraction to each other’s positions and/or orientations) during a collective movement results in a consensus across individuals’ directional preferences in both real and simulated animal groups [20,21]. We use a conceptual model, agent-based simulations, and empirical data from a herd of freeranging goats (Capra aegagrus hircus) at the edge of the Namib Desert, to distinguish patterns of motion that represent voting or copying
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
