This response outlines more reasons why we need the integrative framework of grandparental investments and intergenerational transfers that we advocated in the target article. We discusses obstacles that stand in the way of such a framework and of a better understanding of the effects of grandparenting in the developed world. We highlight new research directions that have emerged from the commentaries, and we end by discussing some of the things in our target article about which we may have been wrong.

What motivates grandparents to their altruism? We review answers from evolutionary theory, sociology, and economics. Sometimes in direct conflict with each other, these accounts of grandparental investment exist side-by-side, with little or no theoretical integration. They all account for some of the data, and none account for all of it. We call for a more comprehensive theoretical framework of grandparental investment that addresses its proximate and ultimate causes, and its variability due to lineage, values, norms, institutions (e.g., inheritance laws), and (...) social welfare regimes. This framework needs to take into account that the demographic shift to low fecundity and mortality in economically developed countries has profoundly altered basic parameters of grandparental investment. We then turn to the possible impact of grandparental acts of altruism, and examine whether benefits of grandparental care in industrialized societies may manifest in terms of less tangible dimensions, such as the grandchildren's cognitive and verbal ability, mental health, and well-being. Although grandparents in industrialized societies continue to invest substantial amounts of time and money in their grandchildren, we find a paucity of studies investigating the influence that this investment has on grandchildren in low-risk family contexts. Under circumstances of duress there is converging evidence that grandparents can provide support that helps to safeguard their children and grandchildren against adverse risks. We conclude by discussing the role that grandparents could play in what has been referred to as Europe's demographic suicide. (shrink)

This commentary cites evidence to argue that girls growing up in a competitive and aggressive environment are more likely to shift to avoidant attachment than to ambivalent attachment in middle childhood. These avoidant women are also more likely to favor a short-term mating strategy. The role of oxytocin (OT) and early experience in shaping an avoidant attachment in females is also discussed.

Benefits to females of short-term mating have recently been identified, and it has been suggested that women have evolved adaptations for this strategy. One piece of evidence supporting such a female adaptation would be that women find the experience of a one-night stand as affectively positive as men. Individuals (N = 1,743) who had experienced a one-night stand were asked to rate aspects of their “morning after” feelings (six positive and six negative). Women were significantly more negative and less positive (...) than men. Although women did not especially view these relationships as a prelude to long-term relationships, they felt greater regret than men about having been “used.” Extra-pair copulations were rated more negatively, but not less positively, than singles’ experiences. There was no interaction between gender and mated status on positivity or negativity. Although, in terms of subsequent affective response, women do not seem well adapted to casual sexual encounters, it may be important to distinguish impelling sexual motivation preceding intercourse from later evaluations of the event. Menstrual cycle changes may also be important in altering the strength and target of sexual motivation. (shrink)

Contemporary mate preferences can provide important clues to human reproductive history. Little is known about which characteristics people value in potential mates. Five predictions were made about sex differences in human mate preferences based on evolutionary conceptions of parental investment, sexual selection, human reproductive capacity, and sexual asymmetries regarding certainty of paternity versus maternity. The predictions centered on how each sex valued earning capacity, ambition— industriousness, youth, physical attractiveness, and chastity. Predictions were tested in data from 37 samples drawn from (...) 33 countries located on six continents and five islands. For 27 countries, demographic data on actual age at marriage provided a validity check on questionnaire data. Females were found to value cues toresource acquisitionin potential mates more highly than males. Characteristics signalingreproductive capacitywere valued more by males than by females. These sex differences may reflect different evolutionary selection pressures on human males and females; they provide powerful cross-cultural evidence of current sex differences in reproductive strategies. Discussion focuses on proximate mechanisms underlying mate preferences, consequences for human intrasexual competition, and the limitations of this study. (shrink)

Contemporary mate preferences can provide important clues to human reproductive history. Little is known about which characteristics people value in potential mates. Five predictions were made about sex differences in human mate preferences based on evolutionary conceptions of parental investment, sexual selection, human reproductive capacity, and sexual asymmetries regarding certainty of paternity versus maternity. The predictions centered on how each sex valued earning capacity, ambition— industriousness, youth, physical attractiveness, and chastity. Predictions were tested in data from 37 samples drawn from (...) 33 countries located on six continents and five islands. For 27 countries, demographic data on actual age at marriage provided a validity check on questionnaire data. Females were found to value cues toresource acquisitionin potential mates more highly than males. Characteristics signalingreproductive capacitywere valued more by males than by females. These sex differences may reflect different evolutionary selection pressures on human males and females; they provide powerful cross-cultural evidence of current sex differences in reproductive strategies. Discussion focuses on proximate mechanisms underlying mate preferences, consequences for human intrasexual competition, and the limitations of this study. (shrink)

The ‘death of evidence’ issue in Canada raises the spectre of politicized science, and thus the question of what role social values may have in science and how this meshes with objectivity and evidence. I first criticize philosophical accounts that have to separate different steps of research to restrict the influence of social and other non-epistemic values. A prominent account that social values may play a role even in the context of theory acceptance is the argument from inductive risk. It (...) maintains that the more severe the social consequences of erroneously accepting a theory would be, the more evidence is needed before the theory may be accepted. However, an implication of this position is that increasing evidence makes the impact of social values converge to zero; and I argue for a stronger role for social values. On this position, social values may determine a theory’s conditions of adequacy, which among other things can include co.. (shrink)

It is hypothesized from within an evolutionary framework that females should be less invested in peer relations than males. Investment was operationalized as enjoyment in Study 1 and as preference for interaction in Study 2. In the first study, four- and six-year-old children’s enjoyment of peer interaction was observed in 26 groups of same-sex peers. Girls were rated as enjoying their interactions significantly less than boys. In the second study, six- and nine-year-old children were interviewed about the individuals with whom (...) they spend time in their homes and neighborhoods and about the individuals who participate in their favorite activities. The proportion of individuals named by children who were peers was significantly lower for girls than boys both in children’s neighborhoods and in children’s favorite activities. Results strongly support the hypothesis that females and males have evolved differential preferences for interaction with peers. (shrink)

We have identified a sample of 53 societies outside of the classical Himalayan and Marquesean area that permit polyandrous unions. Our goal is to broadly describe the demographic, social, marital, and economic characteristics of these societies and to evaluate some hypotheses of the causes of polyandry. We demonstrate that although polyandry is rare it is not as rare as commonly believed, is found worldwide, and is most common in egalitarian societies. We also argue that polyandry likely existed during early human (...) history and should be examined from an evolutionary perspective. Our analysis reveals that it may be a predictable response to a high operational sex ratio favoring males and may also be a response to high rates of male mortality and, possibly, male absenteeism. Other factors may contribute, but our within-polyandry sample limits analysis. (shrink)

I argue for a deflationary answer to the question, “What is it to be a woman?” Prior attempts by feminist theorists to provide a metaphysical account of what all and only women have in common have all failed for the same reason: there is nothing women have in common beyond being women. Although the social kinds man and woman are primitive, their existence can be explained. I say that human sex difference is the material ground of systems of gender; gender (...) systems serve to enable male control of female reproductive capacities. This explains the fact that most women are female, but it does not entail that all women are female or that all females are women. To clarify my position, I draw an analogy between the kind woman and the kind parent. While it is difficult to come up with necessary and sufficient conditions for being a parent, it is clear that the social institution or practice of parenting has its material ground in the biological facts about human reproduction together with facts about infantile dependency. Saying this does not entail that all and only biological progenitors are parents. (shrink)

The “reproductive suppression hypothesis” states that the strong desire of adolescent girls in our culture to control their weight may reflect the operation of an adaptive mechanism by which ancestral women controlled the timing of their sexual maturation and hence first reproduction, in response to cues about the probable success of reproduction in the current situation. We develop a model based on this hypothesis and explore its behavior and evolutionary and psychological implications across a range of parameter values. We use (...) the process of model development to identify assumptions implicit in the reproductive suppression hypothesis and variables that need to be measured in order to investigate it more fully. In addition, because costs were probably associated with weight control, an important part of this analysis is the specification of situations in which the benefits of adaptive adjustment of the maturation schedule could have outweighed the costs of achieving that adjustment by slowing adolescent weight gain. (shrink)

Feminist epistemology has often been understood as the study of feminine "ways of knowing." But feminist epistemology is better understood as the branch of naturalized, social epistemology that studies the various influences of norms and conceptions of gender and gendered interests and experiences on the production of knowledge. This understanding avoids dubious claims about feminine cognitive differences and enables feminist research in various disciplines to pose deep internal critiques of mainstream research.

This essay is a case study of the self-destruction that occurs in the work of a social-constructionist historian of science who embraces a radical philosophy of science. It focuses on Thomas Laqueur's Making Sex: Body and Gender from the Greeks to Freud in arguing that a history of science committed to the social construction of science and to the central theses of Kuhnian, Duhemian, and Quinean philosophy of science is incoherent through self-reference. Laqueur's text is examined in detail in order (...) to make the main point; a similar phenomenon in the work of the feminist historian of science Evelyn Fox Keller is then briefly discussed. (shrink)

In a recent issue of this journal, Vandermassen suggested that feminists should include sexual selection theory and evolutionary psychology in a unifying theory of human nature. In response, this article aims to offer some insight into the development of sexual selection theory, to caution against Vandermassen's unreserved assimilation and to promote the opposite ongoing integration — an inclusion of gender perspectives into evolutionary biology. In society today, opinions about maintaining traditional sex roles are often put forward on the basis of (...) what is natural and how animals behave. However, the natural sciences have proved to be pervaded by gendered values and interests; Darwin's theory of sexual selection has been criticized for being male biased, and partly due to the unwillingness of Darwin's scientific contemporaries to accept female choice, research has been overwhelmingly focused on males. More recently, theory has become less gender biased and research has come to include a large variety of issues not present in the first version of the theory. However, there is a need to increase the awareness of gender bias in order to develop a gender-neutral evolutionary biology. (shrink)

Of articles which are submitted for publication in Philosophy, a surprisingly large proportion are about the views of Richard Rorty. Some, indeed, we have published. They, along with pretty well all the articles we receive on Professor Rorty, are highly critical. On the perverse assumption that there must be something to be said for anyone who attracts widespread hostility, it is only right to see what can be said in favour of Rorty's latest collection of papers, entitled, Truth and Progress.

Of articles which are submitted for publication in Philosophy, a surprisingly large proportion are about the views of Richard Rorty. Some, indeed, we have published. They, along with pretty well all the articles we receive on Professor Rorty, are highly critical. On the perverse assumption that there must be something to be said for anyone who attracts widespread hostility, it is only right to see what can be said in favour of Rorty's latest collection of papers, entitled, Truth and Progress.

Feminist philosophers of biology bring the tools of feminist theory, and in particular the tools of feminist philosophy of science, to investigations of the life sciences. While the critical examination of the categories of sex and gender (which will be explained below) takes a central place, the methods, ontological assumptions, and foundational concepts of biology more generally have also enjoyed considerable feminist scrutiny. Through such investigations, feminist philosophers of biology reveal the extent to which the theory and practice of particular (...) scientific disciplines and research programs (and, indeed, their philosophical study) are intertwined with both value judgments and social hierarchies. (shrink)

Tomasello, Kruger & Ratner relate the evolution of social cognition – the understanding of others' minds – to the evolution of culture. Tomasello et al. conceive of the accumulation of culture as the product of cultural learning, a kind of learning dependent upon recognizing others' intentionality. They distinguish three levels of this recognition: of intention (what isxtrying to do), of beliefs (what doesxthink aboutp), and of beliefs about beliefs (what doesxthinkythinks aboutp). They then tie these levels to three discrete forms (...) of cultural learning – imitative, instructed, and collaborative – which children become capable of when they are 9 months, 4 years, and 6 years old respectively, at least in Western culture where relevant data are available. (shrink)

Tomasello, Kruger & Ratner deserve congratulations for their well-reasoned ideas on the development of cultural learning. Their arguments are generally convincing, perhaps because their distinctions and developmental relations among types of cultural learning and agency mirror concepts of my own.

Tomasello, Kruger & Ratner make the very interesting and valid point that the transmission of culture must depend on understanding others' minds. Culture is shared among a people and is passed on to progeny. The sharing of culture implies that the purpose of (and therefore the meaning behind) any given cultural element (behavioral tradition, word, or artifact) is understood. Because meaning or purpose emanates from minds, something about others' minds must be understood in order to truly learn some element of (...) a culture. It thus makes sense that cultural learning should depend on social-cognitive skills. But what exactly is cultural learning?There are two rival interpretations of the term cultural learning. In the first, one would define a given type of cultural learning by the type of social-cognitive skill it entails. For example, imitative learning would be defined as any learning of a cultural element in which another's goals or intentions are taken into account. This definition of cultural learning, however, would force Tomasello et al.'s argument into a circle: Imitative learning relies on this social-cognitive skill because imitative learning is defined as learning that relies on this social-cognitive skill. Such a circular definition does not do their argument justice. (shrink)

Contrary to chimpanzees and bonobos, humans display long-term exclusive relationships between males and females. Probably all human cultures have some kind of marriage system, apparently designed to protect these exclusive relationships and the resulting offspring in a potentially sexual competitive environment. Different hypotheses about the origin of human pair-bonds are compared and it is shown how they may refer to different phases of human evolution.