9,516 research outputs found
Replication strategies and the evolution of cooperation by exploitation
No full textIntroducing the concept of replication strategies this paper studies the evolution of cooperation in populations of agents whose offspring follow a social strategy that is determined by a parent's replication strategy. Importantly, social and replication strategies may differ, thus allowing parents to construct their own social niche, defined by the behaviour of their offspring. We analyse the co-evolution of social and replication strategies in well-mixed and spatial populations. In well-mixed populations, cooperation-supporting equilibria can only exist if the transmission processes of social strategies and replication strategies are completely separate. In space, cooperation can evolve without complete separation of the timescales at which both strategy traits are propagated. Cooperation then evolves through the presence of offspring exploiting defectors whose presence and spatial arrangement can shield clusters of pure cooperators
Game theoretic treatments of social niche construction: How do the conditions for cooperation evolve?
No full textThe presence of cooperation has long puzzled evolutionary biologists; the resolution to this puzzle is often attributed to population structure. While the effects of population structure on cooperation are understood, less is known regarding how population structure is itself subject to evolution. The research program of Social Niche Construction (SNC) explores these issues. This thesis presents three related papers that further our understanding of SNC and addresses a number of issues within the research program.Firstly, I demonstrate that diploid organisms under the presence of meiotic drive represents an example of SNC; where assortative mating plays the role of the social niche modifier. I thus argue that assortative mating may be an adaptation that overcomes meiotic drive.Secondly, I present a formal argument for why a gene that causes individuals to assort cannot invade a population of freely-mixed defectors at equilibrium. I present a potential solution to this problem; namely, that if individuals engage in multiple simultaneous cooperative dilemmas, then there may be a continued selection pressure for increased assortment.Lastly, I present a model for the evolution of a cooperative division of labour. Previous gametheoretic definitions assume cooperation to be a single behaviour. I argue that this is too narrow, as often the benefits of cooperation come about through the interaction of differing types. To address this issue I define a class of games; which I call Division of Labour (DOL) games, that have the property that fitness is maximised by a mixture of different types. I show that DOL games are not resolved by a positive assortment on phenotype; instead mean fitness is maximised by positive assortment on a genotype that can exhibit phenotypic plasticity; i.e. express multiple phenotypes conditionally upon social environment.Together these models broaden and deepen our understanding of how population structure evolves and how SNC transforms social dilemmas and modifies social outcomes.<br/
A tale of two theorems: Comment on “Universal scaling for the dilemma strength in evolutionary games” by Z. Wang et al.
No full textCooperation and the division of labour
No full textCooperation is vital for maintaining the integrity of complex life forms. In many cases in nature cooperation manifests it-self through constituent parts performing different, but complementary, functions. The vast majority of studies on the evolution of cooperation, however, look only at the special case in which cooperation manifests itself via the constituent parts performing identical tasks. In this paper we investigate a class of games in which the socially optimal behaviour has the property of being heterogeneous. We show that this class of games is equivalent to a region of ST space (the space of normalised two-player games characterised by the ‘sucker’ and ‘temptation’ payoffs) which has previously been dismissed. We analyse, through a simple group selection model, properties that evolving agents would need to have in order to “solve” this dilemma. Specifically we find that positive assortment on pure strategies may lower mean individual pay-off, and that assortment on mixed strategies will increase pay-off, but not maximise it
Charlie May Simon materials
No full textThis collection contains materials relating to Arkansas author Charlie May Simon
The evolution of assortment with multiple simultaneous games
No full textCurrent theories of social evolution predict the direction of selection for a given level of assortment. What remains unclear is how to determine the direction of selection on assortment itself if this were subject to evolutionary change. Here we define and analyse a simple model that allows us to investigate the evolution of assortment. We find that there is only a positive selection gradient for increased assortment if the population is polymorphic in the cooperative trait. We further show that if the individuals in question engage in multiple cooperative dilemmas simultaneously then there may be a continued selection on increased assortment which is ultimatelysufficient to resolve severe dilemmas such as the prisoner’s dilemma
Hamilton’s rule in non-additive games
No full textRecently a number of authors have questioned both the validity and utility of inclusive fitness. One particular claim is that Hamilton’s rule applies only to additive games. Additive games represent a vanishingly small subset of all games and do not capture a number of interesting qualitative behaviours which are present in non-additive games. Thus, if these criticisms were correct, inclusive fitness would be a severely limited theoretical tool. We show these criticisms are not valid by demonstrating that any symmetric game can be transformed into an additive payoff matrix in such a way that the action of selection remains unchanged. The result comes with a caveat, however, which is that terms in the payoff matrix must themselves be frequency dependent. Despite this, we demonstrate the utility of inclusive fitness by means of applying Hamilton’s rule to two such non-additive games. The central claim of inclusive fitness is that relatedness is the key to cooperation, we show that this remains true even for non-additive games
Game theoretic treatments for the differentiation of functional roles in the transition to multicellularity
No full textMulticellular organisms are characterised by role specialisation, brought about by the epigenetic differentiation of their constituent parts. Conventional game theoretic studies of cooperation do not account for this division of labour, nor do they allow for the possibility of the plastic expression of phenotype. We address these issues by extending the notion of cooperative dilemmas to account for such interaction in which heterogeneous roles are advantageous and present an extended dynamical model of selection that allows for the possibility of conditional expression of phenotype. We use these models to investigate systematically when selection will favour an adaptive diversification of roles. We argue that such extensions to models and concepts are necessary to understand the origins of multicellularity and development
Simon Nyakot
No full textabstract: Simon Nyakot left his village when he was six years old.
“Lost Boys Found” is an ongoing, interdisciplinary project that is collecting, recording and archiving the oral histories of the Lost Boys/Girls of Sudan. The collection is a work-in-progress, seeking to record the oral history of as many Lost Boys/Girls as are willing, and will be used in a future book.Age: 27Region: LakeThis picture and bio was donated to the Lost Boys Found project from The Arizona Lost Boys Cente
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