Modeling the emergence of modular leadership hierarchy during the collective motion of herds made of harems

Gregarious animals need to make collective decisions in order to keep their cohesiveness. Several species of them live in multilevel societies, and form herds composed of smaller communities. We present a model for the development of a leadership hierarchy in a herd consisting of loosely connected sub-groups (e.g. harems) by combining self organization and social dynamics. It starts from unfamiliar individuals without relationships and reproduces the emergence of a hierarchical and modular leadership network that promotes an effective spreading of the decisions from more capable individuals to the others, and thus gives rise to a beneficial collective decision. Our results stemming from the model are in a good agreement with our observations of a Przewalski horse herd (Hortob\'agy, Hungary). We find that the harem-leader to harem-member ratio observed in Przewalski horses corresponds to an optimal network in this approach regarding common success, and that the observed and modeled harem size distributions are close to a lognormal.Comment: 18 pages, 7 figures, J. Stat. Phys. (2014

Organization of R&D With Two Agents and Principal

In order to deliver an innovation principals employ competing agents in some circumstances, while employing research team in other circumstances. This paper compares various structures of R&D to provide a rational behind this observation. It is assumed, that the principal can employ either one agent, two competing agents or two agents, cooperating in a team. Which of the available structures will be chosen by principal, depends on value of prize in stake, technological benefits of team production and team structure. Due to the positive effect on incentives, competing agents always generate larger profit to the principal, than a single agent. Further, they often perform better than the team, even when the latter has significant technological benefits. However, the performance of the team may be improved, if it is organized as a hierarchy with the team leader (who is responsible for allocation of resources) and his subordinate. The paper provides conditions on parameters, which determine whether the principal should employ a team or competing agents for performing R&D.moral hazard, hierarchy, team production, competition, organization of R&D