This paper attempts to reconcile critics and defenders of inclusive fitness by constructing a synthesis that does justice to the insights of both. I argue that criticisms of the regression-based version of Hamilton’s rule, although they undermine its use for predictive purposes, do not undermine its use as an organizing framework for social evolution research. I argue that the assumptions underlying the concept of inclusive fitness, conceived as a causal property of an individual organism, are unlikely (...) to be exactly true in real populations, but they are approximately true given a specific type of weak selection that Hamilton took, on independent grounds, to be responsible for the cumulative assembly of complex adaptation. Finally, I reflect on the uses and limitations of “design thinking” in social evolution research. The debate about the foundations of inclusive fitness theory that has followed in the wake of Nowak, Tarnita and Wilson’s critique has been remarkably polarizing. After several rounds of rebuttals and replies, there is still little evidence of any serious reconciliation between the theory’s critics and its defenders. It doesn’t have to be this way. I believe that, on the main points of disagreement, it is possible to find a way forward that does justice to the insights of both camps. My aim in this paper is to find that way forward. (shrink)

Inclusive fitness has been under intense scrutiny in recent years, with many critics claiming the framework leads to incorrect predictions. We consider one particularly influential heuristic for estimating inclusive fitness in the context of the very case that motivated reliance on it to begin with: the Sir Philip Sidney signalling game played with relatives. Using a neighbour-modulated fitness model, we show when and why this heuristic is problematic. We argue that reliance on the heuristic rests (...) on a misunderstanding of what it means for two organisms to be related and perpetuates a mischaracterization of the role of the ‘relatedness’ parameter in inclusive fitness. _1_ Introduction _2_ Heuristic Inclusive Fitness _3_ The Sir Philip Sidney Game _4_ Model _5_ Results _6_ Conclusion Appendix. (shrink)

I distinguish two roles for a fitness concept in the context of explaining cumulative adaptive evolution: fitness as a predictor of gene frequency change, and fitness as a criterion for phenotypic improvement. Critics of inclusive fitness argue, correctly, that it is not an ideal fitness concept for the purpose of predicting gene-frequency change, since it relies on assumptions about the causal structure of social interaction that are unlikely to be exactly true in real populations, (...) and that hold as approximations only given a specific type of weak selection. However, Hamilton took this type of weak selection, on independent grounds, to be responsible for cumulative assembly of complex adaptations. In this special context, I argue that inclusive fitness is distinctively valuable as a criterion for improvement and a standard for optimality. Yet to call inclusive fitness a criterion for improvement and a standard for optimality is not to make any claim about the frequency with which inclusive fitness optimization actually occurs in nature. This is an empirical question that cannot be settled by theory alone. I close with some reflections on the place of inclusive fitness in the long running clash between ‘causalist’ and ‘statisticalist’ conceptions of fitness. (shrink)

Individual-as-maximizing agent analogies result in a simple understanding of the functioning of the biological world. Identifying the conditions under which individuals can be regarded as fitness maximizing agents is thus of considerable interest to biologists. Here, we compare different concepts of fitness maximization, and discuss within a single framework the relationship between Hamilton’s (J Theor Biol 7:1–16, 1964) model of social interactions, Grafen’s (J Evol Biol 20:1243–1254, 2007a) formal Darwinism project, and the idea of evolutionary stable strategies. We (...) distinguish cases where phenotypic effects are additive separable or not, the latter not being covered by Grafen’s analysis. In both cases it is possible to define a maximand, in the form of an objective function ϕ(z), whose argument is the phenotype of an individual and whose derivative is proportional to Hamilton’s inclusive fitness effect. However, this maximand can be identified with the expression for fecundity or fitness only in the case of additive separable phenotypic effects, making individual-as-maximizing agent analogies unattractive (although formally correct) under general situations of social interactions. We also feel that there is an inconsistency in Grafen’s characterization of the solution of his maximization program by use of inclusive fitness arguments. His results are in conflict with those on evolutionary stable strategies obtained by applying inclusive fitness theory, and can be repaired only by changing the definition of the problem. (shrink)

Altruism is a central concept in evolutionary biology. Evolutionary biologists still disagree about its meaning (E.O. Wilson 2005; Fletcher et al. 2006; D.S. Wilson 2008; Foster et al. 2006a, b; West et al. 2007a, 2008). Semantic disagreement appears to be quite robust and not easily overcome by attempts at clarification, suggesting that substantive conceptual issues lurk in the background. Briefly, group selection theorists define altruism as any trait that makes altruists losers to selfish traits within groups, and makes groups of (...) altruists fitter than groups of non-altruists. Inclusive fitness theorists reject a definition based on within- and between-group fitness. Traits are altruistic only if they cause a direct and absolute fitness loss to the donor. The latter definition is more restrictive and rejects as cases of altruism behaviors that are accepted by the former. Fletcher and Doebeli (2009) recently proposed a simple, direct and individually based fitness approach, which they claim returns to first principles: carriers of the genotype of interest “must, on average, end up with more net direct fitness benefits than average population members.” This seductively simple proposal uses the concept of assortment to explain how diverse kinds of altruists end up on average with more net fitness than their non-altruistic rivals. In this paper I shall argue that their approach implies a new concept of altruism that contrasts with and improves on the concept of the inclusive fitness approach. (shrink)

Inclusive fitness theory provides conditions for the evolutionary success of a gene. These conditions ensure that the gene is selfish in the sense of Dawkins (The selfish gene, Oxford University Press, Oxford, 1976): genes do not and cannot sacrifice their own fitness on behalf of the reproductive population. Therefore, while natural selection explains the appearance of design in the living world (Dawkins in The blind watchmaker: why the evidence of evolution reveals a universe without design, W. W. (...) Norton, New York, 1996), inclusive fitness theory does not explain how. Indeed, Hamilton’s rule is equally compatible with the evolutionary success of prosocial altruistic genes and antisocial predatory genes, whereas only the former, which account for the appearance of design, predominate in successful organisms. Inclusive fitness theory, however, permits a formulation of the central problem of sociobiology in a particularly poignant form: how do interactions among loci induce utterly selfish genes to collaborate, or to predispose their carriers to collaborate, in promoting the fitness of their carriers? Inclusive fitness theory, because it abstracts from synergistic interactions among loci, does not answer this question. Fitness-enhancing collaboration among loci in the genome of a reproductive population requires suppressing alleles that decrease, and promoting alleles that increase the fitness of its carriers. Suppression and promotion are effected by regulatory networks of genes, each of which is itself utterly selfish. This implies that genes, and a fortiori individuals in a social species, do not maximize inclusive fitness but rather interact strategically in complex ways. It is the task of sociobiology to model these complex interactions. (shrink)

ABSTRACT In social evolution theory, biological individuals are often represented on the model of rational agents, that is, as if they were ‘seeking’ to maximize their own reproductive success. In the 1990s, important criticisms of this mode of thinking were made by Brian Skyrms and Elliott Sober, who both argued that ‘rational agent’ models can lead to incorrect predictions when there are positive correlations between individuals’ phenotypes. In this article, I argue that one model of rational choice—namely, Savage’s model —can (...) actually be vindicated in evolutionary biology, provided that the pay-offs are computed in inclusive fitness terms. I also show that the use of this model is better avoided when pay-offs are non-additive, or when certain causal influences affect the outcome of natural selection. The result is a partial rehabilitation of this mode of thinking, conditional on both the additivity of the pay-off structure and the absence of any form of manipulation or coercion. _1_ Introduction _2_ When Natural Selection and Rational Deliberation Part Ways _3_ A Simple Solution: Redefining the Pay-offs in Inclusive Fitness Terms _4_ Sober on Inclusive Fitness Maximization _5_ Inclusive Fitness with Non-additive Pay-offs _6_ Causal Influences and the Savage– Hamilton Model _6.1_ Reciprocity and partner choice _6.2_ Coercion and manipulation _7_ Conclusion Appendix. (shrink)

Philosophers have shown that the Aristotelian conception of mind and body is capable of resolving the problems confronting dualism. In this paper the resolution of the mind–body problem is extended with a scientific solution by integrating the Aristotelian framework with evolutionary theory. It is discussed how the theories of Fisher and Hamilton enable us to construct and solve hypotheses about how the mind evolved out of matter. These hypotheses are illustrated by two examples: the evolutionary transition from cells to multicellular (...) organisms, and the evolutionary transition from babbling to doing things with words and later reasoning and giving reasons. The first transitions resulted in the sensitive psyche of the other animals, the second in the rational psyche of humans. It is discussed how exploratory behaviour of lower-level entities facilitated these evolutionary transitions. (shrink)

This article is about the analogy between inclusive fitness and utility. In behavioral ecology, it is often assumed that individual organisms behave as if they were “striving” to maximize their inclusive fitness—a measure analogue to the kind of utility function that is used to represent the preferences of rational agents. Here, I explore some conceptual puzzles related to this view and question whether the kind of biological utility posited by the advocates of the “maximizing agent analogy” (...) can be adequately interpreted in inclusive fitness terms. (shrink)

We show how Richard Jeffrey’s The Logic of Decision provides the proper formalism for calculating expected fitness for correlated encounters in general. As an illustration, some puzzles about kin selection are resolved.

We show how Richard Jeffrey's The Logic of Decision provides the proper formalism for calculating expected fitness for correlated encounters in general. As an illustration, some puzzles about kin selection are resolved.

This article analyzes the recent debate surrounding inclusive fitness and argues that certain limitations ascribed to it by critics—such as requiring weak selection or providing dynamically insufficient models—are better thought of as limitations of the methodological framework most often used with inclusive fitness. In support of this, I show how inclusive fitness can be used with the replicator dynamics. I conclude that much of the debate is best understood as being about the orthogonal issue (...) of using abstract versus idealized models. (shrink)

Grouping severe mental disorders into a global category is likely to lead to a “theory of everything” which forcefully explains everything and nothing. Speculation even at the phenotypic level of the single disorder cannot be fruitful, unless specific and testable models are proposed. Inclusive fitness must be incorporated in such models. (Published Online November 9 2006).

Hamilton’s theory of inclusive fitness is a widely used framework for studying the evolution of social behavior, but controversy surrounds its status. Hamilton originally derived his famous rb > c rule for the spread of a social gene by assuming additivity of costs and benefits. However, it has recently been argued that the additivity assumption can be dispensed with, so long as the −c and b terms are suitably defined, as partial regression coefficients. I argue that this way (...) of generalizing Hamilton’s rule to the nonadditive case, while formally correct, faces conceptual problems. (shrink)

Hamilton’s theory of inclusive fitness is a widely used framework for studying the evolution of social behavior, but controversy surrounds its status. Hamilton originally derived his famous rb > c rule for the spread of a social gene by assuming additivity of costs and benefits. However, it has recently been argued that the additivity assumption can be dispensed with, so long as the −c and b terms are suitably defined, as partial regression coefficients. I argue that this way (...) of generalizing Hamilton’s rule to the nonadditive case, while formally correct, faces conceptual problems. (shrink)

Hamilton introduced two conceptions of social fitness, which he called neighbour-modulated fitness and inclusive fitness. Although he regarded them as formally equivalent, a re-analysis of his own argument for their equivalence brings out two important assumptions on which it rests: weak additivity and actor's control. When weak additivity breaks down, neither fitness concept is appropriate in its original form. When actor's control breaks down, neighbour-modulated fitness may be appropriate, but inclusive fitness is (...) not. Yet I argue that, despite its more limited domain of application, inclusive fitness provides a distinctively valuable perspective on social evolution. (shrink)

Following Wallace’s suggestion, Darwin framed his theory using Spencer’s expression “survival of the fittest”. Since then, fitness occupies a significant place in the conventional understanding of Darwinism, even though the explicit meaning of the term ‘fitness’ is rarely stated. In this paper I examine some of the different roles that fitness has played in the development of the theory. Whereas the meaning of fitness was originally understood in ecological terms, it took a statistical turn in terms (...) of reproductive success throughout the 20th Century. This has lead to the ever-increasing importance of sexually reproducing organisms and the populations they compose in evolutionary explanations. I will argue that, moving forward, evolutionary theory should look back at its ecological roots in order to be more inclusive in the type of systems it examines. Many biological systems can only be satisfactorily accounted for by offering a non-reproductive account of fitness. This argument will be made by examining biological systems with very small or transient population structures. I argue this has significant consequences for how we define Darwinism, increasing the significance of survival over that of reproduction. (shrink)

This article describes and defends an inclusive anti-canonical approach to the study of the history of philosophy. Its proposal, based on an analysis of the nature of the history of philosophy and the value of engaging in the practice, is this: The history of philosophy is the history of rationally justified, systematic answers to philosophical questions; studying this subject is both intrinsically and instrumentally valuable; these benefits do not derive from the imposition of a canon—indeed, there should be no (...) canon; the absence of a canon leaves room for a thousand courses on a thousand different topics with a thousand different narrative structures; but a good syllabus should be relevantly diverse in a way that fits the thematic arc of the course; and this prescription for the discipline is inclusive, in ways that can only strengthen and enliven it for future generations. (shrink)

The public controversy over genetically modified crops is predominantly framed in terms of concerns over health and safety. Within this framing, the primary point of controversy is whether GM foods are likely to cause bio-physiological injury or disease to human consumers; a secondary issue, but one that still fits within the health and safety framing, is whether the cultivation of GM crops is likely to cause bio-physiological injury or disease to non-target species or ecosystems more broadly. Proponents of the development (...) and... (shrink)

ABSTRACT Research suggests that ethical leadership affects employee behavior and organizational functioning. This study aimed to determine the relationship between EL and productive energy, as mediated by person-organizational fit. The study used assumptions of the social learning and social exchange theories that posit that leadership has a direct impact on employee behavior, mainly through role modeling and the reciprocal nature thereof. An empirical paradigm using a cross sectional quantitative design was used. The PE instrument was assessed for construct validity within (...) the South African context. The analysis included a comparison between the private and public sectors, emphasizing the importance of context as differentiator. Relatively high, statistically significant correlations were found between the variables for both sectors and the combined sample. The hierarchical regression analysis indicated that 18% of the variance in PE is explained by EL. This model was improved by the inclusion of POF. The conceptual model was confirmed with structural equation modeling. The findings of this study suggest that EL has a significantly positive effect on PE and POF, which mediates the relationship between EL and PE. Sectoral differences were reported. (shrink)

People with severe learning disability are particularly difficult to include in the research process. As a result, researchers may be tempted to focus on those with learning disability who can be included. The problem is exacerbated in this field as the political agenda of inclusion and involvement is driven by those people with learning disability who are the higher functioning. To overcome this we should first detach the notion of consent from ideas about autonomy and think instead of it as (...) a way to avoid wronging others; this fits the original historical use of consent in research. This allows us to think in terms of including participants to the best of their abilities rather than in terms of a threshold of autonomy. Researchers could then use imaginative ways to include the least able and to ensure they are not wronged in research or by exclusion from it. (shrink)

My purpose in this paper is to set forth a case for inclusion, without any restriction whatsoever, of gays and lesbians in the legal definition of marriage within the various jurisdictions within the United States of America. Historical and cross cultural definitions of marriage are usually based on two basic premises or components, structure and function. Structural definitions of marriage, with which most people and jurisdictions identify, are based on exclusion and inclusion, i.e. on who is eligible for inclusion and (...) who must be excluded. Ordinarily the restrictions exclude those not having reached the age of majority, those who are not judged mentally competent, and those of the same gender. Functional definitions of marriage are based on the willingness of the partners to engage in the duties and responsibilities to each other and to all offspring regardless of their physical or mental fitness. I intend to defend the proposition that legal marriage for gays and lesbians is better defined and defended when based on function rather than structure. Specifically, this means that marriage is the union of those who 1.) without mental equivocation embrace their mutual commitment to support and care for each other; 2.) are of legal age; 3.) are of sound mind; and 4.) affirm their commitment to fulfill, to the best of their ability, the following functions as they pertain to the natural birth, legal adoption, or foster care of any and all children included in the marital union: These functions include but are not limited to: protection , economic, affect-giving, socialization, acculturation, education, and sexual access between the conjugal partners. Historically, there is no record throughout the history of humankind, of any state or body politic that does not profess a vested interest in the mate selection patterns of its young. This is not generally for the edification of the married, but rather for the assurance of the socialization and acculturation of the ascending generation. (shrink)

Paradox is a complex notion that has assumed a diverse range of forms within philosophy, and Søren Kierkegaard contributes one of the more interesting variations by employing a fairy tale to introduce what he identifies as the absolute paradox of the Incarnation. Despite this, more recent discussion on paradox has given little attention to Kierkegaard and has largely bracketed out any interaction with paradox that does not fit within the general analytic framework. In this paper, I evaluate the different characterizations (...) of paradox offered by Kierkegaard and representative thinkers in the analytic tradition. I argue that the non-bracketing of Kierkegaard’s fairy tale as a valid form of paradox discourse not only provides a fuller account of paradox but also offers a critique of the attempt to exclude any form of paradox from philosophical discussion that does not already conform to the restrictions of the analytic approach. (shrink)

Drawing on Merleau-Ponty’s “lived body” theory, we argue for a shift towards a lived-experience and body-specific curriculum in South Africa. Such a curriculum would view learning as a lived, embodied, social and culturally contextualised field. Its central aim would be to draw the learner into a plane of consciousness conducive to being awakened to the act of learning through an attitude of full attention. We specifically use the term “body-specific” to imply, as opposed to a one-size-fits-all curriculum model, one in (...) which lived experience and the “body” form the conceptual basis on which the curriculum is built. Consequently, we reject the orthodox cognitive conception of the curriculum which views learning as a mental exercise oriented towards the acquisition of pre-designed knowledge that is “outer fixed” and “inner constructed”. In contrast, we propose that learning should be outwardly constructed through lived experience and inwardly fixed as knowledge develops against the pre-noetic background of the lived world. Underpinning this is the essentially Merleau-Pontian notion that the knowledge we hold originates from our relationships with this world that are embodied in experience, and our engagements within society and culture. The “inner” and “outer” shift in learning infers a switch from pure, disciplinary, homogeneous, expert-led, supply-driven, hierarchical, peer-reviewed and almost exclusively university-based learning to experience-based, applied, problem-centred, trans-disciplinary, heterogeneous, hybrid, demand-driven learning. In such a curriculum, the role of the teacher would be to focus on how the world arranges itself around the learner and to guide learners to see how the world reveals itself to them through their personal lived experience. (shrink)

From mitochondria to meerkats, the natural world is full of spectacular examples of social behaviour. In the early 1960s W. D. Hamilton changed the way we think about how such behaviour evolves. He introduced three key innovations - now known as Hamilton's rule, kin selection, and inclusive fitness - and his pioneering work kick-started a research program now known as social evolution theory. This is a book about the philosophical foundations and future prospects of that program. [Note: only (...) the Introduction is available to download.]. (shrink)

Several modern commentators of Dignaga have puzzled over the 5th century Buddhist philosopher1s theory of the triple condition of the inferential sign. Th. Stcherbatsky (1932), Richard Hayes (1988) and Bimal K. Matilal (1986) have wondered at the reasons for Dignaga’s insistence on the inclusion of the secondcondition, which seems to be the logical equivalent of the third condition. Do the three criteria together furnish patterns of valid inference which differ from those patterns furnished by criteria one and three alone? In (...) this paper, I detail three types of cases which underline the importance of the inclusion of the second criterion. (shrink)

Supporting Hamilton’s inclusive fitness theory, archival analyses of inheritance patterns in wills have revealed that people invest more of their estates in kin of closer genetic relatedness. Recent classroom experiments have shown that this genetic relatedness effect is stronger for relatives of direct lineage (children, grandchildren) than for relatives of collateral lineage (siblings, nieces, nephews). In the present research, multilevel modeling of more than 1,000 British Columbian wills revealed a positive effect of genetic relatedness on proportions of estates (...) allocated to relatives. This effect was qualified by an interaction with lineage, such that it was stronger for direct than for collateral relatives. Exploratory analyses of the moderating role of benefactors’ sex and estate values showed the genetic relatedness effect was stronger among female and wealthier benefactors. The importance of these moderators to understanding kin investment in modern humans is discussed. (shrink)

Hamilton’s theory of kin selection is the best-known framework for understanding the evolution of social behavior but has long been a source of controversy in evolutionary biology. A recent critique of the theory by Nowak, Tarnita, and Wilson sparked a new round of debate, which shows no signs of abating. In this overview, we highlight a number of conceptual issues that lie at the heart of the current debate. We begin by emphasizing that there are various alternative formulations of Hamilton’s (...) rule, including a general version, which is always true; an proximate version, which assumes weak selection; and a special version, which demands other restrictive assumptions. We then examine the relationship between the neighbor-modulated fitness and inclusive fitness approaches to kin selection. Finally, we consider the often-strained relationship between the theories of kin and multilevel selection. (shrink)

This PhD dissertation examines the conceptual and theoretical foundations of the most general and most widely used framework for understanding social evolution, W. D. Hamilton's theory of kin selection. While the core idea is intuitive enough (when organisms share genes, they sometimes have an evolutionary incentive to help one another), its apparent simplicity masks a host of conceptual subtleties, and the theory has proved a perennial source of controversy in evolutionary biology. To move towards a resolution of these controversies, we (...) need a careful and rigorous analysis of the philosophical foundations of the theory. My aim in this work is to provide such an analysis. I begin with an examination of the concepts behavioural ecologists employ to describe and classify types of social behaviour. I stress the need to distinguish concepts that are often conflated: for example, we need to distinguish simple cooperation from collaboration in collective tasks, behaviours from strategies, and control from manipulation and coercion. I proceed from here to the formal representation of kin selection via George R. Price’s covariance selection mathematics. I address a number of interpretative issues the Price formalism raises, including the vexed question of whether kin selection theory is ‘formally equivalent’ to multi-level selection theory. In the second half of the dissertation, I assess the uses and limits of Hamilton’s rule for the evolution of social behaviour; I provide a precise statement of the conditions under which the rival neighbour-modulated fitness and inclusive fitness approaches in contemporary kin selection theory are equivalent (and describe cases in which they are not); and I criticize recent formal attempts to establish the controversial claim that kin selection leads to organisms behaving as if maximizing their inclusive fitness. (shrink)

Cooperation is rife in the microbial world, yet our best current theories of the evolution of cooperation were developed with multicellular animals in mind. Hamilton’s theory of inclusive fitness is an important case in point: applying the theory in a microbial setting is far from straightforward, as social evolution in microbes has a number of distinctive features that the theory was never intended to capture. In this article, I focus on the conceptual challenges posed by the project of (...) extending Hamilton’s theory to accommodate the effects of gene mobility. I begin by outlining the basics of the theory of inclusive fitness, emphasizing the role that the concept of relatedness is intended to play. I then provide a brief history of this concept, showing how, over the past fifty years, it has departed from the intuitive notion of genealogical kinship to encompass a range of generalized measures of genetic similarity. I proceed to argue that gene mobility forces a further revision of the concept. The reason in short is that, when the genes implicated in producing social behaviour are mobile, we cannot talk of an organism’s genotype simpliciter; we can talk only of an organism’s genotype at a particular stage in its life cycle. We must therefore ask: with respect to which stage(s) in the life cycle should relatedness be evaluated? For instance: is it genetic similarity at the time of social interaction that matters to the evolution of social behaviour, or is it genetic similarity at the time of reproduction? I argue that, strictly speaking, it is neither of these: what really matters to the evolution of social behaviour is diachronic genetic similarity between the producers of fitness benefits at the time they produce them and the recipients of those benefits at the end of their life-cycle. I close by discussing the implications of this result. The main payoff is that it makes room for a possible new mechanism for the evolution of altruism in microbes that does not require correlated interaction among bearers of the genes for altruism. The importance of this mechanism in nature remains an open empirical question. (shrink)

Phenomena like meat sharing in hunter-gatherers, self-sacrifice in intergroup conflicts, and voluntary contribution to public goods provision in laboratory experiments have led to the development of numerous theories on the evolution of altruistic in-group beneficial behavior in humans. Many of these theories abstract away from the effects of kinship on the incentives for public goods provision, though. Here, it is investigated analytically how genetic relatedness changes the incentive structure of that paradigmatic game which is conventionally used to model and experimentally (...) investigate collective action problems: the linear public goods game. Using recent anthropological data sets on relatedness in 61 contemporary hunter-gatherer and horticulturalist societies the relevant parameters of this model are then estimated. It turns out that the kinship patterns observed in these societies substantially reduce the negative effect of increasing group size on incentives for public goods provision. It is suggested, therefore, that renewed attention should be given to inclusive fitness theory in the context of public goods provision also in sizable groups, because its explanatory power with respect to this central problem in the evolution of human cooperativeness and altruism might have been substantially underrated. (shrink)

This paper addresses methodological and metatheoretical aspects of the ongoing debate over the adaptive significance of Tibetan polyandry. Methodological contributions include a means of estimating relatedness of fraternal co-husbands given multigenerational polyandry, and use of Hamilton’s rule and a member-joiner model to specify how inclusive fitness gains of co-husbands may vary according to seniority, opportunity costs, and group size. These methods are applied to various data sets, particularly that of Crook and Crook (1988). The metatheoretical discussion pivots on (...) the critique by evolutionary psychologists of adaptationist accounts of polyandry. Contrary to this critique, I argue that valid adaptationist explanations of such practices do not necessitate cognitive mechanisms evolved specifically to produce polyandry, nor that there must have been exact equivalents of Tibetan agricultural estates and social institutions in human evolutionary history. Specific issues raised when one posits either kin selection or cultural evolution to explain the adaptive features of Tibetan polyandry are also discussed. (shrink)

The kinship theory of genomic imprinting predicts that imprinted genes affect parent–child and child–child interactions. During prenatal and neonatal stages, patrigenes promote selfish and matrigenes altruistic behavior. Models predict that this imprinted gene expression pattern is reversed starting with the juvenile stage. This article explores possible effects of imprinted genes on nonverbal and simple and complex linguistic behaviors before and after the reversal. A hypothesis is discussed that is based on the observation language evolved as a new form of communicative (...) behavior. Inclusive fitness theory is used for explaining how and why new forms of communicative behaviors evolved as an extension of behaviors and gestures displayed by our predecessors. The hypothesis is elaborated through discussing a scenario of early language evolution. This scenario is used for explaining early stages in child development and for discussing possible effects of patrigenes and matrigenes on the development of children’s communicative behaviors. (shrink)

Two questions are raised for Grafen’s formal darwinism project of aligning evolutionary dynamics under natural selection with the optimization of phenotypes for individuals of a population. The first question concerns mean fitness maximization during frequency-dependent selection; in such selection regimes, not only is mean fitness typically not maximized but it is implausible that any parameter closely related to fitness is being maximized. The second question concerns whether natural selection on inclusive fitness differences can be regarded (...) as individual selection or whether it leads to a departure from the central motivation that led to the formal darwinism project, viz., to show that “Darwinian” evolution through individual selection leads to “good design” or phenotypic adaptation through trait optimization. (shrink)

I argue that Grafen’s formal darwinism project could profitably incorporate a gene’s-eye view, as informed by the major transitions framework. In this, instead of the individual being assumed to maximise its inclusive fitness, genes are assumed to maximise their inclusive fitness. Maximisation of fitness at the individual level is not a straightforward concept because the major transitions framework shows that there are several kinds of biological individual. In addition, individuals have a definable fitness, exhibit (...) individual-level adaptations and arise in a major transition, only to the extent that the inclusive-fitness interests of genes within them coincide. Therefore, as others have suggested, the fundamental level at which fitness is maximised is the gene level. Previous reconciliations of the concepts of gene-level fitness and individual-level fitness implicitly recognise this point. Adaptations always maximise the fitness of their causative genes, but may be simple or complex. Simple adaptations may be controlled by single genes and be maladaptive at higher levels, whereas complex adaptations are controlled by multiple genes and rely on those genes having coinciding fitness interests at a higher level, for a given trait. (shrink)

When we have asked Hadza whether married couples should live with the family of the wife (uxorilocally) or the family of the husband (virilocally), we are often told that young couples should spend the first years of a marriage living with the wife’s family, and then later, after a few children have been born, the couple has more freedom—they can continue to reside with the wife’s kin, or else they could join the husband’s kin, or perhaps live in a camp (...) where there are no close kin. In this paper, we address why shifts in kin coresidence patterns may arise in the later years of a marriage, after the birth of children. To do so, we model the inclusive fitness costs that wives might experience from leaving their own kin and joining their husband’s kin as a function of the number of children in their nuclear family. Our model suggests that such shifts should become less costly to wives as their families grow. This simple model may help explain some of the dynamics of postmarital residence among the Hadza and offer insight into the dynamics of multilocal residence, the most prevalent form of postmarital residence among foragers. (shrink)

Phenomena like meat sharing in hunter-gatherers, altruistic self-sacrifice in intergroup conflicts, and contribution to the production of public goods in laboratory experiments have led to the development of numerous theories trying to explain human prosocial preferences and behavior. Many of these focus on direct and indirect reciprocity, assortment, or (cultural) group selection. Here, I investigate analytically how genetic relatedness changes the incentive structure of that paradigmatic game which is conventionally used to model and experimentally investigate collective action problems: the public (...) goods game. Using data on contemporary hunter-gatherer societies I then estimate a threshold value determining when biological altruism turns into maximizing inclusive fitness in this game. I find that, on average, contributing no less than about 40% of individual fitness to public goods production still is an optimal strategy from an inclusive fitness perspective under plausible socio-ecological conditions. (shrink)

The paper outlines various concepts of rationality, their characteristics and consequences. In the first, most general part, the metaphysical, instrumental and discursive rationality is distinguished. The following part focuses on instrumental rationality and the rational choice theory and ordinal and cardinal utility, expected utility and game theory, respectively. All those concepts are summarised as being the most mathematically elegant and mostly decidable and helpful in the decision-making process. Giving primacy to individual preferences and withholding the judgment on their “objective” value, (...) they are also devoid of double standards. They are, however, strongly normative and weakly coincide with actual agents’ behaviour. Empirical findings on agents’ decision making seem to demonstrate their irrationality, unless we introduce into the analysis different concepts of rationality, namely based on costs efficient heuristics, inclusive fitness and ecological rationality. They are discussed respectively, and although they seem better to explain the set of humans’ seemingly irrational behaviour, they are likely week in predicting that behaviour. They are also losing their normative dimension and thus cease to be helpful in decision making. Applying the particular theory of rationality, either descriptively or normatively, seems to depend strongly on the environment, which can be characterised by its extension from a small to a large world. The more the small world’s features an environment reveals, the more effective is the application of the particular model of rationality. Beyond the small worlds, rule stochasticity, underspecification and misspecification and the only reasonable method are consecutive trials and errors, which eventually may reduce the large world to the small one. (shrink)

Two predictions concerning the perceived severity of crimes can be derived from evolutionary theory. The first, arising from the theory of inclusive fitness, is that crimes in general should be viewed as more serious to the degree that the victim is genetically related to the perpetrator. The second, arising from the deleterious effects of inbreeding depression, is that heterosexual sexual coercion should be perceived as more serious the closer the genetic relationship of victim and perpetrator, particularly when the (...) victim is a female of fertile age. Two hundred and thirty university students estimated the magnitude of the severity of brief crime descriptions in three separate studies. In the first two, the biological kinship of victim and perpetrator was varied, and in the third, the hypothetical genetic relatedness of the subject and the fictitious victim was varied. All three studies found the linear relationships between biological kinship and perceived crime severity predicted by theory. (shrink)

Inclusive fitness theory was not originally designed to explain the major transitions in evolution, but there is a growing consensus that it has the resources to do so. My aim in this paper is to highlight, in a constructive spirit, the puzzles and challenges that remain. I first consider the distinctive aspects of the cooperative interactions we see within the most complex social groups in nature: multicellular organisms and eusocial insect colonies. I then focus on one aspect in (...) particular: the extreme redundancy these societies exhibit. I argue that extreme redundancy poses a distinctive explanatory puzzle for inclusive fitness theory, and I offer a potential solution which casts coercion as the key enabler. I suggest that the general moral to draw from the case is one of guarded optimism: while inclusive fitness is a powerful tool for understanding evolutionary transitions, it must be integrated within a broader framework that recognizes the distinctive problems such transitions present and the distinctive mechanisms by which these problems may be overcome. (shrink)

Inclusive fitness theory provides a compelling explanation for the evolution of altruism among kin. However, a completely satisfactory account of non-kin altruism is still lacking. The present study compared the level of altruism found among siblings with that found among friends and mates and sought to reconcile the findings with an evolutionary explanation for human altruism. Participants (163 males and 156 females) completed a questionnaire about help given to a sibling, friend, or mate. Overall, participants gave friends and (...) mates as much or more help than they gave siblings. However, as the cost of help increased, siblings received a progressively larger share of the help, whereas friends and mates received a progressively smaller share, despite the fact that participants were closer emotionally to friends and mates than they were to siblings. These findings help to explain the relative standing of friends and mates as recipients of altruistic aid. (shrink)

In an incendiary 2010 Nature article, M. A. Nowak, C. E. Tarnita, and E. O. Wilson present a savage critique of the best-known and most widely used framework for the study of social evolution, W. D. Hamilton’s theory of kin selection. More than a hundred biologists have since rallied to the theory’s defence, but Nowak et al. maintain that their arguments ‘stand unrefuted’. Here I consider the most contentious claim Nowak et al. defend: that Hamilton’s rule, the core explanatory principle (...) of kin selection theory, ‘almost never holds’. I first distinguish two versions of Hamilton’s rule in contemporary theory: a special version (HRS) that requires restrictive assumptions, and a general version (HRG) that does not. I then show that Nowak et al. are most charitably construed as arguing that HRS almost never holds, while HRG buys its generality at the expense of explanatory power. While their arguments against HRS are fairly uncontroversial, their arguments against HRG are more contentious, yet these have been largely overlooked in the ensuing furore. I consider the arguments for and against the explanatory value of HRG, with a view to assessing what exactly is at stake in the debate. I suggest that the debate hinges on issues concerning the causal interpretability of regression coefficients, and concerning the explanatory function Hamilton’s rule is intended to serve. (shrink)

A study of twenty-five popular women’s novels and six famous romantic stories has led to the conclusion that such novels and stories are tales of mate selection and mating commitment. Pérusse’s (1994) predictions with respect to mate choice are confirmed by the activities of male and female protagonists in the novels (binomial test,p<.01 in all cases). Males choose mates on the basis of sexual exclusivity and fertility. Females choose mates on the basis of economic factors and parenting potential. As well, (...) male and female characters differ in terms of their display of functional emotions. (shrink)