Evolutionary Stability

Knowledge requires more than mere true belief, and we also tend to
think it is more valuable. I explain the added value that knowledge contributes if its extra ingredient beyond true belief is tracking. I show that the tracking conditions are the unique conditions on knowledge that achieve for those who fulfill them a strict Nash Equilibrium and an Evolutionarily Stable Strategy in what I call the True Belief Game. The added value of these properties, intuitively, includes preparedness and an expectation of survival advantage. On this view knowledge is valuable not because knowledge persists but because it makes the bearer more likely to maintain an appropriate belief state—possibly nonbelief—
through time and changing circumstances. When Socrates concluded that knowledge of the road to Larissa was no more valuable than true belief for the purpose of getting to Larissa, he did not take into account that one might want to be prepared for a possible meeting with a misleading sophist along the way, or for the possibility of road work.

For parasites with a predator-prey life cycle, the completion of the life cycle often depends on consumption of parasitized prey by the predator. In the case of such parasite species the predator and the parasite have common interests and therefore a mutualistic relationship is possible. Some evidence of a predator-parasite mutualism was reported from spotted deer or chital (Axix axis) as a prey species, dhole or Indian wild-dog (Cuon alpinus) as the predator and a protozoan (Sarcocystis axicuonis) as the parasite. We examine here, with the help of a model, the ecological conditions necessary for the evolution and stability of such a mutualistic relationship. A two - level game theory model was designed in which the payoff of a parasite is decided not only by alternative parasite strategies but also by alternative host strategies and vice versa. Conditions for ESS were examined. A tolerant predator strategy and a low or moderately virulent parasite strategy which together constitute...

We here develop a model of pre-play communication that generalizes the cheap-talk approach by allowing players to have a lexicographic preference, second to the payoffs in the underlying game, for honesty. We formalize this by way of an honesty (or truth) correspondence between actions and statements, and postulate two axioms met by natural languages. The model is applied to finite and symmetric two-player games and we establish that honest communication and play of the Pareto dominant Nash equilibrium together characterize the unique evolutionarily stable set in generic and symmetric n×n-coordination games. In particular, this holds even in Aumann's (1990) example of a Pareto dominant equilibrium that is not self-enforcing.

An interesting problem which has been widely investigated is under what circumstances will a society of rational agents realize some particular stable situations, and whether they satisfy the condition of social efficiency? This will crucially depend on how they interact and what information they have when they interact. For instance, when strategic interactions are modeled as coordination games, it is known the evolutionary process selects the risk-dominant equilibrium which is not necessarily efficient. We consider the networks of agents, in which each agent faces several types of the strategic decision problems. We investigate the dynamics of collective decision when each agent adapts the strategy of interaction to its neighbors. We are interested in to show how the society gropes its way towards an equilibrium situation. We show that the society selects the most efficient equilibrium among multiple equilibria when the agents composing it do learn from each other as collective le...

The high level of inversion polymorphism and, correspondingly, the abundance of inversion banding sequences (BSs) of polytene chromosomes in the banding sequence pool of Chironomus species permit scientists to reconstruct the cytogenetic evolution of the genus and to evaluate the role of structural rearrangements in the genome during population divergence and speciation. We performed a quantitative assessment of the important

The application of fractal dimension-based constructs to probe the protein interior dates back to the development of the concept of fractal dimension itself. Numerous approaches have been tried and tested over a course of (almost) 30 years with the aim of elucidating the various facets of symmetry of self-similarity prevalent in the protein interior. In the last 5 years especially, there has been a startling upsurge of research that innovatively stretches the limits of fractal-based studies to present an array of unexpected results on the biophysical properties of protein interior. In this article, we introduce readers to the fundamentals of fractals, reviewing the commonality (and the lack of it) between these approaches before exploring the patterns in the results that they produced. Clustering the approaches in major schools of protein self-similarity studies, we describe the evolution of fractal dimension-based methodologies. The genealogy of approaches (and results) presented here portrays a clear picture of the contemporary state of fractal-based studies in the context of the protein interior. To underline the utility of fractal dimension-based measures further, we have performed a correlation dimension analysis on all of the available non-redundant protein structures, both at the level of an individual protein and at the level of structural domains. In this investigation, we were able to separately quantify the self-similar symmetries in spatial correlation patterns amongst peptide-dipole units, charged amino acids, residues with the π-electron cloud and hydrophobic amino acids. The results revealed that electrostatic environments in the interiors of proteins belonging to 'α/α toroid' (all-α class) and 'PLP-dependent transferase-like' domains (α/β class) are highly conducive. In contrast, the interiors of 'zinc finger design' ('designed proteins') and 'knottins' ('small proteins') were identified as folds with the least conducive electrostatic environments. The fold 'conotoxins' (peptides) could be unambiguously identified as one type with the least stability. The same analyses revealed that peptide-dipoles in the α/β class of proteins, in general, are more correlated to each other than are the peptide-dipoles in proteins belonging to the all-α class. Highly favorable electrostatic milieu in the interiors of TIM-barrel, α/β-hydrolase structures could explain their remarkably conserved (evolutionary) stability from a new light. Finally, we point out certain inherent limitations of fractal constructs before attempting to identify the areas and problems where the implementation of fractal dimension-based constructs can be of paramount help to unearth latent information on protein structural properties.

Is cooperation without central authority stable? If so, how robust is it? Despite what might be the conventional wisdom, The Evolution of Cooperation did not solve this problem deductively. In fact, results obtained later by others seem to have contradicted the book's main message. Reexamining this exceptionally influential work yields a new picture. Part of Axelrod's evolutionary story turns out to be false. But the main intuition, that retaliatory strategies of conditional cooperation are somehow advantaged, proves correct in one specific and significant sense: Under a standard evolutionary dynamic these strategies require the minimal frequency to stabilize. Hence, they support the most robust evolutionary equilibrium: the easiest to reach and retain. Moreover, the less efficient a strategy, the larger is its minimal stabilizing frequency; Hobbesian strategies of pure defection are the least robust. Our main theorems hold for a large class of games that pose diverse cooper...

Sequence folding is known to determine the spatial structure and catalytic function of proteins and nucleic acids. We show here that folding also plays a key role in enhancing the evolutionary stability of the intermolecular recognition necessary for the prevalent mode of catalytic action in replication, namely, in trans, one molecule catalyzing the replication of another copy, rather than itself. This points to a novel aspect of why molecular life is structured as it is, in the context of life as it could be: folding allows limited, structurally localized recognition to be strongly sensitive to global sequence changes, facilitating the evolution of cooperative interactions. RNA secondary structure folding, for example is shown to be able to stabilize the evolution of prolonged functional sequences, using only a part of this length extension for intermolecular recognition, beyond the limits of the (cooperative) error threshold. Such folding could facilitate the evolution of polymera...

The implications of evolutionarily stable behavior in finite populations have recently been explored for a variety of aggregative games. This note proves an intimate relationship between quasi-submodularity and global evolutionary stabil-ity of strategies for these games, ...

Some plants are exclusively pollinated by an insect whose larvae feed on their seeds. The net outcome of a single visit for the plant depends on the number of ovules fertilised by the visitor, the number of eggs laid, and the number of seeds eaten by each larva. Unlike other known plant-seed eater pollinating mutualisms, the globeflower-globeflower fly mutualism (Trollius europaeus-Chiastocheta spp.) is unique in that not only females but also males visit flowers, and both sexes are potential pollinators. I analysed the relative efficiency of Chiastocheta males versus females in transporting pollen and fertilising globeflower ovules. I show that there is no sex-specific morphological adaptation or behaviour to enhance pollen collection and transportation in Chiastocheta flies, and that males contribute to pollination. However, because of their smaller body size, males transport significantly less pollen than females. Less seeds are produced after a visit from a male than after a vis...

Conventions can be narrowly interpreted as coordinated ways of equilibrium play, telling all players which of possibly several equilibria to play or more broadly how to choose in a game without imposing the equilibrium property. Since coordination often takes place before learning about the game, one has to coordinate on a prescribing principle. For the subclass of 2×2-bimatrix games with