The literature on human mate preferences is vast but most data come from studies on college students in complex societies, who represent a thin slice of cultural variation in an evolutionarily novel environment. Here, I present data on the mate preferences of men and women in a society of hunter-gatherers, the Hadza of Tanzania. Hadza men value fertility in a mate more than women do, and women value intelligence more than men do. Women place great importance on men’s foraging, and (...) both sexes rate character as important. Unlike college students, Hadza men place considerable importance on women being hard-working, and Hadza women cite looks about as often as men do. (shrink)

Strong reciprocity is an effective way to promote cooperation. This is especially true when one not only cooperates with cooperators and defects on defectors (second-party punishment) but even punishes those who defect on others (third-party, “altruistic” punishment). Some suggest we humans have a taste for such altruistic punishment and that this was important in the evolution of human cooperation. To assess this we need to look across a wide range of cultures. As part of a cross-cultural project, I played three (...) experimental economics games with the Hadza, who are hunter-gatherers in Tanzania. The Hadza frequently engaged in second-party punishment but they rarely engaged in third-party punishment. Other small-scale societies engaged in less third-party punishment as well. I suggest third-party punishment only became more important in large, complex societies to solve more pressing collective-action problems. (shrink)

Menopause is puzzling because life-history theory predicts there should be no selection for outliving one’s reproductive capacity. Adaptive explanations of menopause offered thus far turn on women’s long-term investment in offspring and grandoffspring, all variations on the grandmother hypothesis. Here, I offer a very different explanation. The patriarch hypothesis proposes that once males became capable of maintaining high status and reproductive access beyond their peak physical condition, selection favored the extension of maximum life span in males. Because the relevant genes (...) were not on the Y chromosome, life span increased in females as well. However, the female reproductive span was constrained by the depletion of viable oocytes, which resulted in menopause. (shrink)

A new hypothesis is proposed to explain the perennially enlarged breasts of human females. The nubility hypothesis proposes that hominid females evolved protruding breasts because the size and shape of breasts function as an honest signal of residual reproductive value. Hominid females with greater residual reproductive value were preferred by males once reliable cues to ovulation were lost and long-term bonding evolved. This adaptation was favored because female-female competition for investing males increased once hominid males began to provide valuable resources.

We present a cross-cultural analysis showing that the presence of an active or moral High God in societies varies generally along a continuum from lesser to greater technological complexity and subsistence productivity. Foragers are least likely to have High Gods. Horticulturalists and agriculturalists are more likely. Pastoralists are most likely, though they are less easily positioned along the productivity continuum. We suggest that belief in moral High Gods was fostered by emerging leaders in societies dependent on resources that were difficult (...) to manage and defend without group cooperation. These leaders used the concept of a supernatural moral enforcer to manipulate others into cooperating, which resulted in greater productivity. Reproductive success would accrue most to such leaders, but the average reproductive success of all individuals in the society would also increase with greater productivity. Supernatural enforcement of moral codes maintained social cohesion and allowed for further population growth, giving one society an advantage in competition with others. (shrink)

We use data collected among Hadza hunter-gatherers between 2005 and 2009 to examine hypotheses about the causes and consequences of men’s foraging and food sharing. We find that Hadza men foraged for a range of food types, including fruit, honey, small animals, and large game. Large game were shared not like common goods, but in ways that significantly advantaged producers’ households. Food sharing and consumption data show that men channeled the foods they produced to their wives, children, and their consanguineal (...) and affinal kin living in other households. On average, single men brought food to camp on 28% of days, married men without children at home on 31% of days, and married men with children at home on 42% of days. Married men brought fruit, the least widely shared resource, to camp significantly more often than single men. A model of the relationship between hunting success and household food consumption indicates that the best hunters provided 3–4 times the amount of food to their families than median or poor hunters. These new data fill important gaps in our knowledge of the subsistence economy of the Hadza and uphold predictions derived from the household and kin provisioning hypotheses. Key evidence and assumptions backing prior claims that Hadza hunting is largely a form of status competition were not replicated in our study. In light of this, family provisioning is a more viable explanation for why good hunters are preferred as husbands and have higher fertility than others. (shrink)

Prior to agriculture, human societies were small, with little variation for good genes sexual selection (GGSS) to work on. Across cultures, variation in paternal care makes the benefits of GGSS highly variable. Despite these caveats, female preferences for traits like male body symmetry suggest one reason for female short-term mating is gene shopping.

Humans have a much longer juvenile period (weaning to first reproduction, 14 or more years) than their closest relatives (chimpanzees, 8 years). Three explanations are prominent in the literature. (a) Humans need the extra time to learn their complex subsistence techniques. (b) Among mammals, since length of the juvenile period bears a constant relationship to adult lifespan, the human juvenile period is just as expected. We therefore only need to explain the elongated adult lifespan, which can be explained by the (...) opportunity for older individuals to increase their fitness by providing for grandchildren. (c) The recent model by Kaplan and colleagues suggests that longevity and investment in "embodied capital" will coevolve, and that the need to learn subsistence technology contributed to selection for our extended lifespan.We report experiments designed to test the first explanation: human subsistence technology takes many years to learn, and spending more time learning it gives reproductive benefits that outweight lost time. Taking away some of this time should lead to deficits in efficiency. We paid Hadza foragers to participate in tests of important subsistence skills. We compared efficiency of males and females at digging tubers. They differ greatly in time spent practicing digging but show no difference in efficiency. Children who lost "bush experience" by spending years in boarding school performed no worse at digging tubers or target archery than those who had spent their entire lives in the bush. Climbing baobab trees, an important and dangerous skill, showed no change with age among those who attempted it. We could show no effects of practice time.These findings do not support what we label "the practice theory," but we discuss ways in which the theory could be defended; for example, some as-yet-untested skill may be greatly impaired by loss of a few years of the juvenile period. Our data also show that it is not safe to assume that increases in skill with age are entirely due to learning or practice; they may instead be due to increases in size and strength. (shrink)

Cooperative child care among humans, where individuals other than the biological mother (allomothers) provide care, may increase a mother’s fertility and the survivorship of her children. Although the potential benefits to the mother are clear, the motivations for allomothers to provide care are less clear. Here, we evaluate the kin selection allomothering hypothesis using observations on Hadza hunter-gatherers collected in ten camps over 17 months. Our results indicate that related allomothers spend the largest percentage of time holding children. The higher (...) the degree of relatedness among kin, the more time they spend holding, supporting the hypothesis of nepotism as the strongest motivation for providing allomaternal care. Unrelated helpers of all ages also provide a substantial amount of investment, which may be motivated by learning to mother, reciprocity, or coercion. (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)

Using questionnaire data completed by 170 men, we examine variation in paternal investment in relation to the trade-off between mating and parenting. We found that as men’s self-perceived mate value increases, so does their mating effort, and in turn, as mating effort increases, paternal investment decreases. This study also simultaneously examined the influence on parental investment of men’s mating effort, men’s perception of their mates’ fidelity, and their perceived resemblance to their offspring. All predicted investment. The predictors of investment are (...) also tested independently for men who are still in a relationship with the mother of their children and those that are separated from her. Finally we examine how self-perceived mate value affects how men respond to variation in paternity confidence. Men with a self-perceived low mate value were less likely to respond to lowered mate fidelity by reducing their parental investment compared with men with a self-perceived high mate value. (shrink)

Among hunter-gatherers, the sharing of male and female foods is often assumed to result in virtually the same diet for males and females. Although food sharing is widespread among the hunting and gathering Hadza of Tanzania, women were observed eating significantly more tubers than men. This study investigates the relationship between patterns of dental wear, diet, and extramasticatory use of teeth among the Hadza. Casts of the upper dentitions were made from molds taken from 126 adults and scored according to (...) the Murphy dental attrition scoring system. Females had significantly greater anterior occlusal wear than males when we controlled for age. Males exhibited greater asymmetry in wear, with greater wear on the left side in canines, first premolars, and first molars. We suggest that these sex differences in wear patterns reflect the differences seen in the diet, as well as in the use of teeth as tools. (shrink)

Researchers from across the social sciences have found consistent deviations from the predictions of the canonical model of self-interest in hundreds of experiments from around the world. This research, however, cannot determine whether the uniformity results from universal patterns of human behavior or from the limited cultural variation available among the university students used in virtually all prior experimental work. To address this, we undertook a cross-cultural study of behavior in ultimatum, public goods, and dictator games in a range of (...) small-scale societies exhibiting a wide variety of economic and cultural conditions. We found, first, that the canonical model – based on self-interest – fails in all of the societies studied. Second, our data reveal substantially more behavioral variability across social groups than has been found in previous research. Third, group-level differences in economic organization and the structure of social interactions explain a substantial portion of the behavioral variation across societies: the higher the degree of market integration and the higher the payoffs to cooperation in everyday life, the greater the level of prosociality expressed in experimental games. Fourth, the available individual-level economic and demographic variables do not consistently explain game behavior, either within or across groups. Fifth, in many cases experimental play appears to reflect the common interactional patterns of everyday life. Key Words: altruism; cooperation; cross-cultural research; experimental economics; game theory; ultimatum game; public goods game; self-interest. (shrink)

Recent studies of the evolution of religion have revealed the cognitive underpinnings of belief in supernatural agents, the role of ritual in promoting cooperation, and the contribution of morally punishing high gods to the growth and stabilization of human society. The universality of religion across human society points to a deep evolutionary past. However, specific traits of nascent religiosity, and the sequence in which they emerged, have remained unknown. Here we reconstruct the evolution of religious beliefs and behaviors in early (...) modern humans using a global sample of hunter-gatherers and seven traits describing hunter-gatherer religiosity: animism, belief in an afterlife, shamanism, ancestor worship, high gods, and worship of ancestors or high gods who are active in human affairs. We reconstruct ancestral character states using a time-calibrated supertree based on published phylogenetic trees and linguistic classification and then test for correlated evolution between the characters and for the direction of cultural change. Results indicate that the oldest trait of religion, present in the most recent common ancestor of present-day hunter-gatherers, was animism, in agreement with long-standing beliefs about the fundamental role of this trait. Belief in an afterlife emerged, followed by shamanism and ancestor worship. Ancestor spirits or high gods who are active in human affairs were absent in early humans, suggesting a deep history for the egalitarian nature of hunter-gatherer societies. There is a significant positive relationship between most characters investigated, but the trait “high gods” stands apart, suggesting that belief in a single creator deity can emerge in a society regardless of other aspects of its religion. (shrink)

We would like to thank the commentators for their generous comments, valuable insights and helpful suggestions. We begin this response by discussing the selfishness axiom and the importance of the preferences, beliefs, and constraints framework as a way of modeling some of the proximate influences on human behavior. Next, we broaden the discussion to ultimate-level (that is evolutionary) explanations, where we review and clarify gene-culture coevolutionary theory, and then tackle the possibility that evolutionary approaches that exclude culture might be sufficient (...) to explain the data. Finally, we consider various methodological and epistemological concerns expressed by our commentators. (shrink)

This study builds on the work of contemporary civic republicans, supplying a detailed analysis of the concept of domination absent in the familiar accounts of political freedom as non-domination.

We attempt to extend the nominalistic project initiated in Hartry Field's Science Without Numbers to modern physical theories based in differential geometry.

Machiavellians are manipulative and deceitful individuals willing to utilize any strategy or behavior needed to attain their goals. This study explores what occurs when Machiavellian employees have a Machiavellian leader with the same negative, manipulative disposition. We argue that Machiavellian employees have a negative worldview and are likely to trust their leaders less. This reduced trust likely results in these employees experiencing higher stress and engaging in more unethical behavior. In addition, we expect these negative relationships to be exacerbated when (...) such followers experience Machiavellian leadership. Thus, we test a moderated mediation model assessing whether Machiavellianism affects employees and whether combining Machiavellian leaders and Machiavellian employees is toxic in the sense of exacerbating the negative impact of Machiavellianism on employee trust. Results do not support the proposed conditional indirect effect of trust for either stress or unethical behavior. Instead, we find a conditional direct effect of employee Machiavellianism on both trust and stress: When Machiavellian employees have Machiavellian leaders, their trust in their leader significantly decreases, and their level of stress significantly increases. We also find support for an unconditional indirect effect of trust for employee stress, Machiavellianism in employees relates to stress via lowered trust in the leader. For unethical behavior, we only find a main effect of employee Machiavellianism. (shrink)

Suppose that two geysers, about one mile apart, erupt at irregular intervals, but usually erupt almost exactly at the same time. One would suspect that they come from a common source, or at least that there is a common cause of their eruptions. And this common cause surely acts before both eruptions take place. This idea, that simultaneous correlated events must have prior common causes, was first made precise by Hans Reichenbach (Reichenbach 1956). It can be used to infer the (...) existence of unobserved and unobservable events, and to infer causal relations from statistical relations. Unfortunately it does not appear to be universally valid, nor is there agreement as to the circumstances in which it is valid. (shrink)

Moral puzzles about actions which bring about very small or what are said to be imperceptible harms or benefits for each of a large number of people are well known. Less well known is an argument by Warren Quinn that standard theories of rationality can lead an agent to end up torturing himself or herself in a completely foreseeable way, and that this shows that standard theories of rationality need to be revised. We show where Quinn's argument goes wrong, and (...) apply this to the moral puzzles. (shrink)

What is it that troubles and preoccupies us about the anxieties and anguishes of social and private life? Have advances in the disciplines of psychoanalysis, psychology or the social sciences in general ministered to our needs in these areas? In this forcefully argued collection of essays, Frank Cioffi examines Wittgenstein's reflections on the comparative claims of clarification and empirical enquiry. Though writing out of admiration and indebtedness, he expresses reservations as to the limits Wittgenstein places on the relevance and (...) desirability of empirical knowledge. His discusssions extend from Wittgenstein's reflections on human sacrifice and other ritual practices dealt with by Frazer to Freud's account of the sources of anxiety, depression, dreams and laughter. He asks both whether it is empirical investigation or more lucid reflection that these phenomena demand, and what kind of question this itself is. (shrink)

The two envelope paradox can be dissolved by looking closely at the connection between conditional and unconditional expectation and by being careful when summing an infinite series of positive and negative terms. The two envelope paradox is not another St. Petersburg paradox and that one does not need to ban talk of infinite expectation values in order to dissolve it. The article ends by posing a new puzzle to do with infinite expectations.

This note argues that a belief is knowledge if it's true, certain (i.e. a full belief) and obtained by a reliable process.

Physicians may justifiably limit patients' refusals of medical interventions when the refusal is based on a negative right to noninterference coupled with a request for an unreasonable alternative.

Frank Kermode is one of our most distinguished and beloved critics of English literature. Here, he contributes a new epilogue to his collection of classic lectures on the relationship of fiction to age-old concepts of apocalyptic chaos and crisis. Prompted by the approach of the millennium, he revisits the book which brings his highly concentrated insights to bear on some of the most unyielding philosophical and aesthetic enigmas. Examining the works of writers from Plato to William Burrows, Kermode shows (...) how they have persistently imposed their "fictions" upon the face of eternity and how these have reflected the apocalyptic spirit. Kermode then discusses literature at a time when new fictive explanations, as used by Spenser and Shakespeare, were being devised to fit a world of uncertain beginning and end. He goes on to deal perceptively with modern literaturewith "traditionalists" such as Yeats, Eliot, and Joyce, as well as contemporary "schismatics," the French "new novelists," and such seminal figures as Jean-Paul Sartre and Samuel Beckett. Whether weighing the difference between modern and earlier modes of apocalyptic thought, considering the degeneration of fiction into myth, or commenting on the vogue of the Absurd, Kermode is distinctly lucid, persuasive, witty, and prodigal of ideas. (shrink)

Inhabitants of low-lying islands flooded due to anthropogenic climate change will lose their territory and thereby their ability to exercise their right to political self-determination. This paper addresses the normative questions which arise when climate change threatens territorial rights. It explores whether the loss of statehood supports a claim to territorial compensation, and if so, how it can be satisfied. The paper concludes that such claims are well founded and that they should be met by providing compensatory territories. After introducing (...) a differentiation between land rights and territorial rights, previous theoretical responses to the problem of sinking islands are criticized. It is argued that states may be required to give up parts of their territory as compensation. The paper develops criteria of sufficiency for compensatory territories and proposes to base their selection process on a negative auction. Since it is unlikely that unsettled compensatory territories that meet the specified requirements are available, the rights of their original inhabitants are discussed. (shrink)

The strongest objection to (15) is that speaker's meaning is defined in terms of commitment, a notion which is itself something of a challenge and for which no definition has been given. This would be a strong reason to prefer a definition in terms of some more tractable concept, all things being equal; but it does not lessen the probability that commitment or some similar notion is indispensable to the definition of speaker's meaning.The philosophical writings discussed in this paper all (...) proceed something like this: Particular cases are discussed and a description is given of the mechanisms by which communication takes place. An attempt is made to say something that applies to all instances of speaker's meaning. Words like ‘analysis’, ‘account’ ‘explanation’, ‘explication’, and ‘theory’ are used here, the suggestion being that the objective is to provide for all cases at once what has already been provided for particular cases-an explanation of how meaning works. What is produced, however, looks like adefinition of speaker's meaning, a statement of necessary and sufficient conditions. This definition is then evaluated largely in terms of what counterexamples it does or does not allow.It seems that there is some tendency to conflate two quite distinct objectives: (i) a theory of speaker's meaning-a general description of how it is that speakers are able to communicate; and (ii) a statement of necessary and sufficient conditions for speaker's meaning. Objective (i) might plausibly be regarded as the goal of the study of communication. Objective (ii) is the definition of a certain intuitive, pretheoretical concept of meaning, which might or might not prove to be an important concept with respect to objective (i). The Gricean mechanism and the notion of conventional meaning, on the other hand, are indispensable to (i)-few instances of speaker's meaning could be adequately described without recourse to at least one of these notions. Thus nothing in this paper should be construed as trying to downgrade the importance of the Gricean mechanism for the theory of communication. If objective (ii) and the Gricean mechanism are not as closely associated as has been claimed, this is, if anything, a reason to doubt the importance of (ii) for the theory of communication. (shrink)

We study hyperdefinable groups, the most general kind of groups interpretable in a simple theory. After developing their basic theory, we prove the appropriate versions of Hrushovski's group quotient theorem and the Weil–Hrushovski group chunk theorem. We also study locally modular hyperdefinable groups and prove that they are bounded-by-Abelian-by-bounded. Finally, we analyze hyperdefinable groups in supersimple theories.

I present a “reduced” version of the fifteen Pragma-dialectical rules and inquire into their theoretical status as necessary conditions for a critical discussion. Questions: In what respect is PD’s non-sufficiency a deficiency, can and must it be remedied? Brief answers: with respect to defining the concept ‘critical discussion,’ possibly, yes, if, and only if, one seeks to identify the concept ‘critical discussion’; no, if PD is for fallacy-detection.

Secular change in sex ratios is examined in relation to experience in the family. Two theoretical perspectives are outlined: Guttentag and Secord’s (1983) adaptation of social exchange theory, and sexual selection theory. Because of large-scale change in number of births and typical age differentials between men and women at marriage, low sex ratios at couple formation ages existed in the U.S. between 1965 and the early 1980s. The currently high sex ratios, however, will persist until the end of the century. (...) High sex ratios appear to be associated with lower divorce rates, male commitment to careers that promise economic rewards, male willingness to engage in child care, higher fertility, and higher rates of sexual violence. Sexual selection theory calls attention to intrasexual competition in the numerically larger sex. (shrink)

Increasing complexities facing physicians negotiating the bedside decision continue to fuel the debate over who is the appropriate party to offer ethics consults, should one be needed, during the decision-making process. Some very good arguments have been put forth on behalf of clinical ethicists as being the proper and best party to engage in ethics consultations. However, serious questions remain about the role of the clinical ethicist and his ability to provide the necessary level of objectivity called for in an (...) ethics consult.I argue that the clinician's professional psyche, or mode of thinking as a professional, leaves him little room to maneuver as an objective and detached third party ethics consultant. Several factors are cited and discussed that greatly influence the analyses applied to a case problem by physicians. The most formidable of these factors are habits and the practice of defensive medicine. I conclude that clinical ethicists are less suited for the overall tasks required of an objective consultant in medical cases that appear to involve insurmountable ethical issues. (shrink)

Tense logics in the bimodal propositional language are investigated with respect to the Finite Model Property. In order to prove positive results techniques from investigations of modal logics above K4 are extended to tense logic. General negative results show the limits of the transfer.