Genetic variation in social influence on mate preferences

Patterns of phenotypic variation arise in part from plasticity owing to social interactions, and these patterns contribute, in turn, to the form of selection that shapes the variation we observe in natural populations. This proximate–ultimate dynamic brings genetic variation in social environments to the forefront of evolutionary theory. However, the extent of this variation remains largely unknown. Here, we use a member of the Enchenopa binotata species complex of treehoppers (Hemiptera: Membracidae) to assess how mate preferences are influenced by genetic variation in the social environment. We used full-sibling split-families as ‘treatment’ social environments, and reared focal females alongside each treatment family, describing the mate preferences of the focal females. With this method, we detected substantial genetic variation in social influence on mate preferences. The mate preferences of focal females varied according to the treatment families along with which they grew up. We discuss the evolutionary implications of the presence of such genetic variation in social influence on mate preferences, including potential contributions to the maintenance of genetic variation, the promotion of divergence, and the adaptive evolution of social effects on fitness-related traits.     

Strong reciprocity, human cooperation, and the enforcement of social norms

This paper provides strong evidence challenging the self-interest assumption that dominates the behavioral sciences and much evolutionary thinking. The evidence indicates that many people have a tendency to voluntarily cooperate, if treated fairly, and to punish noncooperators. We call this behavioral propensity “strong reciprocity” and show empirically that it can lead to almost universal cooperation in circumstances in which purely self-interested behavior would cause a complete breakdown of cooperation. In addition, we show that people are willing to punish those who behaved unfairly towards a third person or who defected in a Prisoner’s Dilemma game with a third person. This suggests that strong reciprocity is a powerful device for the enforcement of social norms involving, for example, food sharing or collective action. Strong reciprocity cannot be rationalized as an adaptive trait by the leading evolutionary theories of human cooperation (in other words, kin selection, reciprocal altruism, indirect reciprocity, and costly signaling theory). However, multilevel selection theories of cultural evolution are consistent with strong reciprocity.     

Delectable Creatures and the Fundamental Reality of Metaphor: Biosemiotics and Animal Mind

This article argues that organisms, defined by a semi-permeable membrane or skin separating organism from environment, are (must be) semiotically alert responders to environments (both Innenwelt and Umwelt). As organisms and environments complexify over time, so, necessarily, does semiotic responsiveness, or ‘semiotic freedom’. In complex environments, semiotic responsiveness necessitates increasing plasticity of discernment, or discrimination. Such judgements, in other words, involve interpretations. The latter, in effect, consist of translations of a range of sign relations which, like metaphor, are based on transfers (carryings over) of meanings or expressions from one semiotic ‘site’ to another. The article argues that what humans describe as ‘metaphor’ (and believe is something which only pertains to human speech and mind and, in essence, is ‘not real’) is, in fact, fundamental to all semiotic and biosemiotic sign processes in all living things. The article first argues that metaphor and mind are immanent in all life, and are evolutionary, and, thus, that animals certainly do have minds. Following Heidegger and then Agamben, the article continues by asking about the place of animal mind in humans, and concludes that, as a kind of ‘night science’, ‘humananimal’ mind is central to the semiotics of Peircean abduction.     

Modelling population dynamics in a unicellular social organism community using a minimal model and evolutionary game theory

Most unicellular organisms live in communities and express different phenotypes. Many efforts have been made to study the population dynamics of such complex communities of cells, coexisting as well-coordinated units. Minimal models based on ordinary differential equations are powerful tools that can help us understand complex phenomena. They represent an appropriate compromise between complexity and tractability; they allow a profound and comprehensive analysis, which is still easy to understand. Evolutionary game theory is another powerful tool that can help us understand the costs and benefits of the decision a particular cell of a unicellular social organism takes when faced with the challenges of the biotic and abiotic environment. This work is a binocular view at the population dynamics of such a community through the objectives of minimal modelling and evolutionary game theory. We test the behaviour of the community of a unicellular social organism at three levels of antibiotic stress. Even in the absence of the antibiotic, spikes in the fraction of resistant cells can be observed indicating the importance of bet hedging. At moderate level of antibiotic stress, we witness cyclic dynamics reminiscent of the renowned rock–paper–scissors game. At a very high level, the resistant type of strategy is the most favourable.     

The evolution of prompt reaction to adverse ties

Background  

In recent years it has been found that the combination of evolutionary game theory with population structures modelled in terms of dynamical graphs, in which individuals are allowed to sever unwanted social ties while keeping the good ones, provides a viable solution to the conundrum of cooperation. It is well known that in reality individuals respond differently to disadvantageous interactions. Yet, the evolutionary mechanism determining the individuals' willingness to sever unfavourable ties remains unclear.     

随机进化稳定性研究进展

在过去的三十多年, 演化博弈理论及其进化稳定对策的概念不仅被广泛地应用于解释动物行为的进化, 而且也被成功地应用于分子生物学、经济学、政治学和社会学等诸多学科。然而, 在随机波动环境中演化博弈动态的随机动力学性质始终没有被清晰地认识, 并且这是一个极具挑战性的理论问题。本文简单介绍了我们最近所提出的随机进化稳定性(stochastic evolutionary stability, SES)的概念。随机进化稳定性不仅是经典进化稳定对策(evolutionarily stably strategy, ESS)概念在随机环境下的自然扩展, 而且为揭示在随机环境中动物行为的演化动态提供一个基本的理论框架。     

Do young rhesus macaques know what others see?: A comparative developmental perspective

Humans undergo robust ontogenetic shifts in the theory of mind capabilities. Are these developmental changes unique to human development or are they shared with other closely related non-human species? To explore this issue, we tested the development of the theory of mind capacities in a population of 236 infant and juvenile rhesus macaques (Macaca mulatta). Using a looking-time method, we examined what developing monkeys know about others’ perceptions. Specifically, we tested whether younger monkeys predict that a person will reach for an object where she last saw it. Overall, we found a significant interaction between a monkey's age and performance on this task (p = .014). Juvenile monkeys (between two and 5 years of age) show a nonsignificant trend towards human infant-like patterns of performance, looking longer during the unexpected condition as compared to the expected condition, though this difference is nonsignificant (p = .09). However, contrary to findings in human infants, infant rhesus macaques show a different trend. Infant monkeys on average look slightly longer on average during the expected condition than the unexpected condition, though this pattern was not significant (p = .06). Our developmental results in monkeys provide some hints about the development of the theory of mind capacities in non-humans. First, young rhesus macaques appear to show some interest in the perception of other agents. Second, young rhesus seems able to make predictions based on the visual perspective of another agent, though the developmental pattern of this ability is not as clear nor as robust as in humans. As such, though an understanding of others’ perceptions is early-emerging in human infants, it may require more experience interacting with other social agents in our non-human relatives.     

Conservation of social effects (Ψ) between two species of Drosophila despite reversal of sexual dimorphism

Indirect genetic effects (IGEs) describe the effect of the genes of social partners on the phenotype of a focal individual. Here, we measure indirect genetic effects using the “coefficient of interaction” (Ψ) to test whether Ψ evolved between Drosophila melanogaster and D. simulans. We compare Ψ for locomotion between ethanol and nonethanol environments in both species, but only D. melanogaster utilizes ethanol ecologically. We find that while sexual dimorphism for locomotion has been reversed in D. simulans, there has been no evolution of social effects between these two species. What did evolve was the interaction between genotype‐specific Ψ and the environment, as D. melanogaster varies unpredictably between environments and D. simulans does not. In this system, this suggests evolutionary lability of sexual dimorphism but a conservation of social effects, which brings forth interesting questions about the role of the social environment in sexual selection.     

The evolution of reciprocity in sizable human groups

The scale and complexity of human cooperation is an important and unresolved evolutionary puzzle. This article uses the finitely repeated n person Prisoners’ Dilemma game to illustrate how sapience can greatly enhance group-selection effects and lead to the evolutionary stability of cooperation in large groups. This affords a simple and direct explanation of the human “exception.”     

The evolution of cultural adaptations: Fijian food taboos protect against dangerous marine toxins

The application of evolutionary theory to understanding the origins of our species'' capacities for social learning has generated key insights into cultural evolution. By focusing on how our psychology has evolved to adaptively extract beliefs and practices by observing others, theorists have hypothesized how social learning can, over generations, give rise to culturally evolved adaptations. While much field research documents the subtle ways in which culturally transmitted beliefs and practices adapt people to their local environments, and much experimental work reveals the predicted patterns of social learning, little research connects real-world adaptive cultural traits to the patterns of transmission predicted by these theories. Addressing this gap, we show how food taboos for pregnant and lactating women in Fiji selectively target the most toxic marine species, effectively reducing a woman''s chances of fish poisoning by 30 per cent during pregnancy and 60 per cent during breastfeeding. We further analyse how these taboos are transmitted, showing support for cultural evolutionary models that combine familial transmission with selective learning from locally prestigious individuals. In addition, we explore how particular aspects of human cognitive processes increase the frequency of some non-adaptive taboos. This case demonstrates how evolutionary theory can be deployed to explain both adaptive and non-adaptive behavioural patterns.     

The psychology of social chess and the evolution of attribution mechanisms: explaining the fundamental attribution error

Theory of mind is the field devoted to understanding how organisms discern the mental states of others. Because mental states are not directly observable, they can only be inferred from observable features of the actor (such as behavior) and the situational context that the actor is in. Social psychologists, who study theory of mind processes under the rubric of attribution research, have shown that people often make a logical error of inference: The “fundamental attribution error” (FAE) is the tendency to assume that an actor's behavior and mental state correspond to a degree that is logically unwarranted by the situation. The social environment in which theory of mind capacities evolved may have influenced attributional processing in ways that could explain the error. In particular, the error could be caused by a psyche that is designed (1) to consider only those noncorresponding mental states (such as deception) that could have fitness consequences to the mind reader; (2) to bias inferences in a way that reduces the costs of erroneous inferences; or (3) to bias inferences in a way that yields reputational benefits. The existing literature is reviewed in light of these hypotheses.     

Parental substance misuse and reproductive timing in offspring: A genetically informed study

Parents with substance misuse provide their children with a potentially risky rearing environment. According to the evolutionary life history theory, such environments steer individuals towards faster reproductive strategy. However, parents providing their children with hazardous environments may also pass on genes associated with early parenthood. In register data on individuals born in Sweden 1973–1993 (N = 2,176,128), the hazard ratio of entering parenthood by age 25 was 1.70 (95% CI 1.69–1.72) and 1.85 (1.82–1.89) among offspring of fathers and mothers with substance misuse, respectively, compared to others. In analyses using an offspring-of-siblings design in three types of parental sibling pairs (half siblings, full siblings and dizygotic twins, and monozygotic twins) increasingly controlling for genetic confounding, associations between parental substance misuse and offspring's early reproduction gradually attenuated. Our results suggest that the association between parental substance misuse and earlier parenthood in offspring is at least partly genetically confounded. Life history theory should be further tested with genetically informative research designs.     

Effect of Spatial Dispersion on Evolutionary Stability: A Two-Phenotype and Two-Patch Model

In this paper, we investigate a simple two-phenotype and two-patch model that incorporates both spatial dispersion and density effects in the evolutionary game dynamics. The migration rates from one patch to another are considered to be patch-dependent but independent of individual’s phenotype. Our main goal is to reveal the dynamical properties of the evolutionary game in a heterogeneous patchy environment. By analyzing the equilibria and their stabilities, we find that the dynamical behavior of the evolutionary game dynamics could be very complicated. Numerical analysis shows that the simple model can have twelve equilibria where four of them are stable. This implies that spatial dispersion can significantly complicate the evolutionary game, and the evolutionary outcome in a patchy environment should depend sensitively on the initial state of the patches.     

Models of cooperation based on the Prisoner's Dilemma and the Snowdrift game

Understanding the mechanisms that can lead to the evolution of cooperation through natural selection is a core problem in biology. Among the various attempts at constructing a theory of cooperation, game theory has played a central role. Here, we review models of cooperation that are based on two simple games: the Prisoner's Dilemma, and the Snowdrift game. Both games are two‐person games with two strategies, to cooperate and to defect, and both games are social dilemmas. In social dilemmas, cooperation is prone to exploitation by defectors, and the average payoff in populations at evolutionary equilibrium is lower than it would be in populations consisting of only cooperators. The difference between the games is that cooperation is not maintained in the Prisoner's Dilemma, but persists in the Snowdrift game at an intermediate frequency. As a consequence, insights gained from studying extensions of the two games differ substantially. We review the most salient results obtained from extensions such as iteration, spatial structure, continuously variable cooperative investments, and multi‐person interactions. Bridging the gap between theoretical and empirical research is one of the main challenges for future studies of cooperation, and we conclude by pointing out a number of promising natural systems in which the theory can be tested experimentally.     

Asymmetric Evolutionary Games

Evolutionary game theory is a powerful framework for studying evolution in populations of interacting individuals. A common assumption in evolutionary game theory is that interactions are symmetric, which means that the players are distinguished by only their strategies. In nature, however, the microscopic interactions between players are nearly always asymmetric due to environmental effects, differing baseline characteristics, and other possible sources of heterogeneity. To model these phenomena, we introduce into evolutionary game theory two broad classes of asymmetric interactions: ecological and genotypic. Ecological asymmetry results from variation in the environments of the players, while genotypic asymmetry is a consequence of the players having differing baseline genotypes. We develop a theory of these forms of asymmetry for games in structured populations and use the classical social dilemmas, the Prisoner’s Dilemma and the Snowdrift Game, for illustrations. Interestingly, asymmetric games reveal essential differences between models of genetic evolution based on reproduction and models of cultural evolution based on imitation that are not apparent in symmetric games.     

Information processing in multigame environments modeling the evolution of sex via punctuated equilibria

Uncertain environments are properly described by probability distributions which, as usual, can be collapsed or conditioned into distributions with reduced uncertainty through the processing of environmental information. Organisms which force this collapse gain evolutionary advantage by being able to employ strategies in a known environment rather than in a merely probable one. The accrued benefit gained from processing information can be precisely quantified by comparing benefits returned using distributions prior to, and after collapse, and these often large and immediate benefits can amply justify the evolutionary cost of information processing systems. More importantly, the evolution of information processing systems must necessarily occur in a predictable evolutionary sequence from less complex to more complex. Practical applications include modeling the evolution of sex modeled here as a sequence from asexual reproduction, to single gene exchange, to gene packet exchange, to same species packet exchange, and finally to sexual reproduction, sexual selection, Red Queen contests and so on. Modeling this sequence requires extensions to game theory originally designed to model a single game, to allow the simultaneous operation of many games. This extension is called a multigame environment. The dynamical evolution of the development sequence shows punctuated equilibria.     

Personal Features of Identification and Uniqueness in the Anthropological Field of Social Discourse

In this article, fashion is understood as a means by which an individual gains access and gradual establishment as a participant in a social environment. Fashion can be seen as the evolution of the expression of specific views on the external expression of a person’s common understanding. Then it is perceived too as an element of clothing and a person’s overall wardrobe. In a broader sense, as shown here, fashion is thought of as a social standard that is fulfilled only when it corresponds to a common cultural perception of the social order. The relevance is determined in particular by the fact that fashion is part of the mass culture and can form the appearance of a person.

Thus we understand fashion as part of mass culture, and its impact on the personal formation and development of people in the modern society becomes the subject of study. In particular, the set of fashion elements of youth is taken, in addition to development in the social environment itself.

The novelty of this study lies in determining that a person perceives fashion not only in the process of his/her professional development but also in the processes of developing their own emotional and personal status. Youth is most vulnerable to this. We have studied university students who were born during the phase of the post-Soviet state’s formation. For the first time results can be presented on the basis of the analysis of that generation, which determines their way of life after the transition period. A further direction and application of this study are in forming a link that will create a correlation between current fashion trends and the opportunities young people have for social adaptation.     

Pervasive,yet idiosyncratic,epistatic pleiotropy during adaptation in a behaviourally complex microbe

Understanding how multiple mutations interact to jointly impact multiple ecologically important traits is critical for creating a robust picture of organismal fitness and the process of adaptation. However, this is complicated by both environmental heterogeneity and the complexity of genotype‐to‐phenotype relationships generated by pleiotropy and epistasis. Moreover, little is known about how pleiotropic and epistatic relationships themselves change over evolutionary time. The soil bacterium Myxococcus xanthus employs several distinct social traits across a range of environments. Here, we use an experimental lineage of M. xanthus that evolved a novel form of social motility to address how interactions between epistasis and pleiotropy evolve. Specifically, we test how mutations accumulated during selection on soft agar pleiotropically affect several other social traits (hard agar motility, predation and spore production). Relationships between changes in swarming rate in the selective environment and the four other traits varied greatly over time in both direction and magnitude, both across timescales of the entire evolutionary lineage and individual evolutionary time steps. We also tested how a previously defined epistatic interaction is pleiotropically expressed across these traits. We found that phenotypic effects of this epistatic interaction were highly correlated between soft and hard agar motility, but were uncorrelated between soft agar motility and predation, and inversely correlated between soft agar motility and spore production. Our results show that ‘epistatic pleiotropy’ varied greatly in magnitude, and often even in sign, across traits and over time, highlighting the necessity of simultaneously considering the interacting complexities of pleiotropy and epistasis when studying the process of adaptation.     

Origins of behavioural variability: categorical and discriminative assessment in serial contests

Can social behaviour be probabilistic? Classical results in evolutionary game theory seem to suggest that recognizable asymmetries between individuals in the likelihood of winning fights (i.e. in resource holding power, RHP) rule out the stable probabilistic behaviour associated with mixed strategies. Here, using a variant of the hawk-dove game, I show that these mixed strategies can be common in asymmetric contests, because opponents of similar RHP benefit by ignoring discernable differences to form RHP equivalence categories. This process of categorizing (i.e. opting not to distinguish an opponent's discernably different RHP from one's own) can be adaptive when assessment is imprecise or expensive and mistakes can lead to dangerous combat. For large RHP differences between opponents, discriminating by acting on the discernable RHP difference is evolutionarily stable. For moderate RHP differences, typically neither categorizing nor discriminating is stable, but categorizing predominates if social interactions are frequent. More frequent interactions imply that the social status ultimately achieved is more important in accumulating fitness; this reduces the probability that a loser in combat will accept the submissive role without additional fighting, where this probability of ‘surrender’ expresses another mixed strategy. These patterns appear to fit the establishment of social relationships in some species for which combat is dangerous, and the analysis represents a step towards understanding the emergence of dominance hierarchies.     

The Environments of Our Hominin Ancestors, Tool-usage, and Scenario Visualization

In this paper, I give an account of how our hominin ancestors evolved a conscious ability I call scenario visualization that enabled them to manufacture novel tools so as to survive and flourish in the ever-changing and complex environments in which they lived. I first present the ideas and arguments put forward by evolutionary psychologists that the mind evolved certain mental capacities as adaptive responses to environmental pressures. Specifically, Steven Mithen thinks that the mind has evolved cognitive fluidity, viz., an ability to exchange information flexibly between and among mental modules. Showing the deficiency in Mithen’s view, I then argue that the flexible exchange of information between and among modules together with scenario visualization is what explains the ability to construct the novel tools needed to survive and flourish in the environments in which our hominin ancestors resided. Finally, I trace the development of the multi-purposed javelin, from its meager beginnings as a stick, in order to illustrate scenario visualization in novel tool manufacturing.