The evolutionary iron law of oligarchy

Social hierarchy is a pervasive element of modern societies, yet almost absent before the advent of agriculture during the Neolithic transition. Despite evidence supporting hierarchy as a product of evolution, it is hard to explain the mechanisms which drove this evolution. For instance, the evolution of followers appears as a paradox because followers receive fewer resources than leaders. The “iron law of oligarchy” proposes that the key to the Neolithic transition lies in the role of leaders in collective decision-making. First, leaders would emerge in response to an increase in group size because leaders speed up decision-making and facilitate coordination. Then, leaders would use their newly acquired influence to bias opinions and group decisions to impose inequality that benefits themselves. This theory has the benefit of explaining the origin of both beneficial and despotic sides of leaders. Yet, its investigation has been limited because of the lack of a formal description of (i) how individuals change with time and (ii) how individuals take collective decisions. Thus, we propose the evolutionary iron law of oligarchy, which reinterprets the iron law in evolutionary terms. We reduce leaders and followers to their capacity to influence and we claim that describing the evolution of this trait under the environmental changes observed at the Neolithic transition is sufficient to explain the emergence of helpful and despotic leaders. To investigate this claim, we build individual-centred models simulating consensus formation — how individuals take collective decisions —and evolutionary dynamics — how individuals change with time. On one hand, our results show that the evolutionary iron law of oligarchy is a viable scenario, which can unify previous theories explaining either the beneficial or despotic side of leaders. On the other hand, we developed a mechanistic model of the iron law of oligarchy which can apply across a range of scenarios, and which show under which conditions the iron law of oligarchy would apply. Finally, our results demonstrate that the iron law of oligarchy goes beyond political sciences and is underwritten by the laws of Darwinian evolution. Understanding the factors driving the emergence of hierarchy and despotism will open new perspectives to design better forms of governance

The evolution of moral rules in a model of indirect reciprocity with private assessment

Moral rules allow humans to cooperate by indirect reciprocity. Yet, it is not clear which moral rules best implement indirect reciprocity and are favoured by natural selection. Previous studies either considered only public assessment, where individuals are deemed good or bad by all others, or compared a subset of possible strategies. Here we fill this gap by identifying which rules are evolutionary stable strategies (ESS) among all possible moral rules while considering private assessment. We develop an analytical model describing the frequency of long-term cooperation, determining when a strategy can be invaded by another. We show that there are numerous ESSs in absence of errors, which however cease to exist when errors are present. We identify the underlying properties of cooperative ESSs. Overall, this paper provides a first exhaustive evolutionary invasion analysis of moral rules considering private assessment. Moreover, this model is extendable to incorporate higher-order rules and other processes

An investigation of the role of leadership in consensus decision-making

Leadership is a widespread phenomena in social organisms and it is recognised to facilitate coordination between individuals. While the role of leadership in group foraging or swarm movement is well understood, it is not clear if leaders would also benefit more complex forms of coordination. In particular, a number of organisms coordinate by consensus decision-making, where individuals explicitly communicate their opinions until they converge toward a common decision. Taking inspiration from physical sciences, we extend a consensus formation model to integrate leaders, which we define by three traits: persuasiveness, talkativeness, and stubbornness. We use numerical simulations to investigate the effect of the number of leaders and their characteristics on the time a group spends to reach consensus, and the bias in the final decision. We show that having a minority of influential individuals (leaders) and a majority of influenceable individuals (followers) reduces the time to reach consensus, but biases the decision towards the preferences of the leaders. This effect emerges solely from the differences in individuals’ personality traits, with the most determinant trait being the talkativeness of the individuals. Overall, we provide a comprehensive investigation of the effects of leaders and their traits on consensus decision-making

From disorganized equality to efficient hierarchy: how group size drives the evolution of hierarchy in human societies

A manifest trend is that larger and more productive human groups shift from distributed to centralized decision-making. Voluntary theories propose that human groups shift to hierarchy to limit scalar stress, i.e. the increase in cost of organization as a group grows. Yet, this hypothesis lacks a mechanistic model to investigate the organizational advantage of hierarchy and its role on its evolution. To fill this gap, we describe social organization by the distribution of individuals’ capacity to influence others. We then integrate this formalization into models of social dynamics and evolutionary dynamics. First, our results demonstrate that hierarchy strongly reduces scalar stress, and that this benefit can emerge solely because leaders and followers differ in their capacity to influence others. Second, the model demonstrates that this benefit can be sufficient to drive the evolution of leader and follower behaviours and ultimately, the transition from small egalitarian to large hierarchical groups

Conspecific and heterospecific pheromones stimulate dispersal of entomopathogenic nematodes during quiescence

Ascaroside pheromones stimulate dispersal, a key nematode behavior to find a new food source. Ascarosides produced by entomopathogenic nematodes (EPNs) drive infective juvenile (IJ) emergence from consumed cadavers and dispersal in soil. Without ascarosides from host cadavers, Steinernema feltiae (EPN) reduce dispersal substantially. To determine whether other Steinernema spp. exhibit the same behavior, we compared S. feltiae and S. carpocapsae IJs without host cadaver pheromones. Unlike S. feltiae, S. carpocapsae IJs continued to disperse. However, S. carpocapsae IJs exhibited a temperature-dependent quiescent period. The IJ quiescent period increased at ≤20 °C but did not appear at ≥25 °C. Consistent with this, S. carpocapsae IJ quiescence increased from 30 min to 24 h at ≤20 °C over 60 days. The quiescent period was overcome by dispersal pheromone extracts of their own, other Steinernema spp. and Heterorhabditis spp. Furthermore, S. carpocapsae IJ ambush foraging associated behaviors (tail standing, waving, and jumping) were unaffected by the absence or presence of host cadaver pheromones. For S. feltiae, IJ dispersal declined at all temperatures tested. Understanding the interaction between foraging strategies and pheromone signals will help uncover molecular mechanisms of host seeking, pathogenicity and practical applications to improve the EPN’s efficacy as biocontrol agents.AFRI (2018-67013-28064)Space Florida Israel Innovation Partnerships (018-057)USDA-ARS (58-6042-6-001)USDA-NIFA Agriculture and Food Research InitiativeU.S. Department of AgricultureNational Institute of Food and AgricultureSmall Business Innovation Research (2017-33610-26808

Trusting Intelligent Machines: Deepening Trust Within Socio-Technical Systems

Intelligent machines have reached capabilities that go beyond a level that a human being can fully comprehend without sufficiently detailed understanding of the underlying mechanisms. The choice of moves in the game Go (generated by Deep Mind?s Alpha Go Zero [1]) are an impressive example of an artificial intelligence system calculating results that even a human expert for the game can hardly retrace [2]. But this is, quite literally, a toy example. In reality, intelligent algorithms are encroaching more and more into our everyday lives, be it through algorithms that recommend products for us to buy, or whole systems such as driverless vehicles. We are delegating ever more aspects of our daily routines to machines, and this trend looks set to continue in the future. Indeed, continued economic growth is set to depend on it. The nature of human-computer interaction in the world that the digital transformation is creating will require (mutual) trust between humans and intelligent, or seemingly intelligent, machines. But what does it mean to trust an intelligent machine? How can trust be established between human societies and intelligent machines

Physics case for an LHCb Upgrade II - Opportunities in flavour physics, and beyond, in the HL-LHC era

The LHCb Upgrade II will fully exploit the flavour-physics opportunities of the HL-LHC, and study additional physics topics that take advantage of the forward acceptance of the LHCb spectrometer. The LHCb Upgrade I will begin operation in 2020. Consolidation will occur, and modest enhancements of the Upgrade I detector will be installed, in Long Shutdown 3 of the LHC (2025) and these are discussed here. The main Upgrade II detector will be installed in long shutdown 4 of the LHC (2030) and will build on the strengths of the current LHCb experiment and the Upgrade I. It will operate at a luminosity up to 2×1034 cm−2s−1, ten times that of the Upgrade I detector. New detector components will improve the intrinsic performance of the experiment in certain key areas. An Expression Of Interest proposing Upgrade II was submitted in February 2017. The physics case for the Upgrade II is presented here in more depth. CP-violating phases will be measured with precisions unattainable at any other envisaged facility. The experiment will probe b → sl+l−and b → dl+l− transitions in both muon and electron decays in modes not accessible at Upgrade I. Minimal flavour violation will be tested with a precision measurement of the ratio of B(B0 → μ+μ−)/B(Bs → μ+μ−). Probing charm CP violation at the 10−5 level may result in its long sought discovery. Major advances in hadron spectroscopy will be possible, which will be powerful probes of low energy QCD. Upgrade II potentially will have the highest sensitivity of all the LHC experiments on the Higgs to charm-quark couplings. Generically, the new physics mass scale probed, for fixed couplings, will almost double compared with the pre-HL-LHC era; this extended reach for flavour physics is similar to that which would be achieved by the HE-LHC proposal for the energy frontier