61,671 research outputs found
Bonabeau hierarchy models revisited
What basic processes generate hierarchy in a collective? The Bonabeau model
provides us a simple mechanism based on randomness which develops
self-organization through both winner/looser effects and relaxation process. A
phase transition between egalitarian and hierarchic states has been found both
analytically and numerically in previous works. In this paper we present a
different approach: by means of a discrete scheme we develop a mean field
approximation that not only reproduces the phase transition but also allows us
to characterize the complexity of hierarchic phase. In the same philosophy, we
study a new version of the Bonabeau model, developed by Stauffer et al. Several
previous works described numerically the presence of a similar phase transition
in this later version. We find surprising results in this model that can be
interpreted properly as the non-existence of phase transition in this version
of Bonabeau model, but a changing in fixed point structure
The Grand Experiment of Communism: Discovering the Trade-off between Equality and Efficiency
This paper aims to explain the rise and fall of communism by exploring the interplay between economic incentives and social preferences transmitted by ideology. We introduce inequality-averse and inefficiency-averse agents and analyze their conflict through the interaction between leaders with economic power and followers with ideological determination. The socioeconomic dynamics of our model generate a pendulum-like switch from markets to a centrally-planned economy abolishing private ownership, and back to restoring market incentives. The grand experiment of communism is thus characterized to have led to the discovery of a trade-off between equality and efficiency at the scale of alternative economic systems. While our focus is on the long-run transitions from capitalism to communism and back observed in the course of the 20-th century, the model also derives conditions under which the two systems converge and become stable.
Power accretion in social systems
We consider a model of power distribution in a social system where a set of agents plays a simple game on
a graph: The probability of winning each round is proportional to the agent’s current power, and the winner
gets more power as a result. We show that when the agents are distributed on simple one-dimensional and
two-dimensional networks, inequality grows naturally up to a certain stationary value characterized by a clear
division between a higher and a lower class of agents. High class agents are separated by one or several lower
class agents which serve as a geometrical barrier preventing further flow of power between them. Moreover,
we consider the effect of redistributive mechanisms, such as proportional (nonprogressive) taxation. Sufficient
taxation will induce a sharp transition towards a more equal society, and we argue that the critical taxation level
is uniquely determined by the system geometry. Interestingly, we find that the roughness and Shannon entropy
of the power distributions are a very useful complement to the standard measures of inequality, such as the Gini
index and the Lorenz curveWe acknowledge financial support from the Spanish Government through
Grants No. FIS2015-69167-C2-1-P, No. FIS2015-66020-C2-
1-P, and No. PGC2018-094763-B-I0
The Grand Experiment of Communism: Discovering the Trade-off between Equality and Efficiency
This paper aims to explain the rise and fall of communism by exploring the interplay between economic incentives and social preferences in different economic systems. We introduce inequality-averse and inefficiency-averse agents responding to economic incentives and transmitting their ideology as they are affected by evolving outcomes. We analyze their conflict through the interaction between leaders with economic power and followers with ideological determination. The socioeconomic dynamics of our model generate a pendulum-like switch from markets to a centrally-planned economy abolishing private ownership, and back to restoring market incentives. The grand experiment of communism is thus characterized to have led to the discovery of a trade-off between equality and efficiency at the scale of alternative economic systems.capitalism, communism, inequality, inefficiency, ideological transmission, economic transititions
Evolutionary connectionism: algorithmic principles underlying the evolution of biological organisation in evo-devo, evo-eco and evolutionary transitions
The mechanisms of variation, selection and inheritance, on which evolution by natural selection depends, are not fixed over evolutionary time. Current evolutionary biology is increasingly focussed on understanding how the evolution of developmental organisations modifies the distribution of phenotypic variation, the evolution of ecological relationships modifies the selective environment, and the evolution of reproductive relationships modifies the heritability of the evolutionary unit. The major transitions in evolution, in particular, involve radical changes in developmental, ecological and reproductive organisations that instantiate variation, selection and inheritance at a higher level of biological organisation. However, current evolutionary theory is poorly equipped to describe how these organisations change over evolutionary time and especially how that results in adaptive complexes at successive scales of organisation (the key problem is that evolution is self-referential, i.e. the products of evolution change the parameters of the evolutionary process). Here we first reinterpret the central open questions in these domains from a perspective that emphasises the common underlying themes. We then synthesise the findings from a developing body of work that is building a new theoretical approach to these questions by converting well-understood theory and results from models of cognitive learning. Specifically, connectionist models of memory and learning demonstrate how simple incremental mechanisms, adjusting the relationships between individually-simple components, can produce organisations that exhibit complex system-level behaviours and improve the adaptive capabilities of the system. We use the term “evolutionary connectionism” to recognise that, by functionally equivalent processes, natural selection acting on the relationships within and between evolutionary entities can result in organisations that produce complex system-level behaviours in evolutionary systems and modify the adaptive capabilities of natural selection over time. We review the evidence supporting the functional equivalences between the domains of learning and of evolution, and discuss the potential for this to resolve conceptual problems in our understanding of the evolution of developmental, ecological and reproductive organisations and, in particular, the major evolutionary transitions
Dynamics of alliance formation and the egalitarian revolution
Arguably the most influential force in human history is the formation of
social coalitions and alliances (i.e., long-lasting coalitions) and their
impact on individual power. In most great ape species, coalitions occur at
individual and group levels and among both kin and non-kin. Nonetheless, ape
societies remain essentially hierarchical, and coalitions rarely weaken social
inequality. In contrast, human hunter-gatherers show a remarkable tendency to
egalitarianism, and human coalitions and alliances occur not only among
individuals and groups, but also among groups of groups. Here, we develop a
stochastic model describing the emergence of networks of allies resulting from
within-group competition for status or mates between individuals utilizing
dyadic information. The model shows that alliances often emerge in a phase
transition-like fashion if the group size, awareness, aggressiveness, and
persuasiveness of individuals are large and the decay rate of individual
affinities is small. With cultural inheritance of social networks, a single
leveling alliance including all group members can emerge in several
generations. Our results suggest that a rapid transition from a hierarchical
society of great apes to an egalitarian society of hunter-gatherers (often
referred to as "egalitarian revolution") could indeed follow an increase in
human cognitive abilities. The establishment of stable group-wide egalitarian
alliances creates conditions promoting the origin of cultural norms favoring
the group interests over those of individuals.Comment: 37 pages, 15 figure
Self-organizing social hierarchies on scale-free networks
In this work we extend the model of Bonabeau et al. in the case of scale-free
networks. A sharp transition is observed from an egalitarian to an hierarchical
society, with a very low population density threshold. The exact threshold
value also depends on the network size. We find that in an hierarchical society
the number of individuals with strong winning attitude is much lower than the
number of the community members that have a low winning probability
Self-organization and time-stability of social hierarchies
The formation and stability of social hierarchies is a question of general
relevance. Here, we propose a simple generalized theoretical model for
establishing social hierarchy via pair-wise interactions between individuals
and investigate its stability. In each interaction or fight, the probability of
"winning" depends solely on the relative societal status of the participants,
and the winner has a gain of status whereas there is an equal loss to the
loser. The interactions are characterized by two parameters. The first
parameter represents how much can be lost, and the second parameter represents
the degree to which even a small difference of status can guarantee a win for
the higher-status individual. Depending on the parameters, the resulting status
distributions reach either a continuous unimodal form or lead to a totalitarian
end state with one high-status individual and all other individuals having
status approaching zero. However, we find that in the latter case long-lived
intermediary distributions often exist, which can give the illusion of a stable
society. As we show, our model allows us to make predictions consistent with
animal interaction data and their evolution over a number of years. Moreover,
by implementing a simple, but realistic rule that restricts interactions to
sufficiently similar-status individuals, the stable or long-lived distributions
acquire high-status structure corresponding to a distinct high-status class.
Using household income as a proxy for societal status in human societies, we
find agreement over their entire range from the low-to-middle-status parts to
the characteristic high-status "tail". We discuss how the model provides a
conceptual framework for understanding the origin of social hierarchy and the
factors which lead to the preservation or deterioration of the societal
structure.Comment: Added sections 4.1 and S2.A about agonistic interactions in animals,
added sections 4.2.1 and S2.B regarding potential proxies for societal status
in non-human animals, added references to sections 1 and 2. Main text: 34
pages, 11 figures. Supplementary appendices: 36 pages, 24 figure
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