Though biologists identify individuals as ‘male’ or ‘female’ across a broad range of animal species, the particular traits exhibited by males and females can vary tremendously. This diversity has led some to conclude that cross-animal sexes (males, or females, of whatever animal species) have “little or no explanatory power” (Dupré 1986: 447) and, thus, are not natural kinds in any traditional sense. This essay will explore considerations for and against this conclusion, ultimately arguing that the animal (...) sexes, properly understood, are “historical explanatory kinds”: groupings that can be scientifically significant even while their members differ radically in their current properties and particular histories. Whether this makes them full-fledged natural kinds is a question I take up at the very end. (shrink)

This study investigated sex differences in interest in infants among children, adolescents, young adults, and older individuals. Interest in infants was assessed with responses to images depicting animal and human infants versus adults, and with verbal responses to questionnaires. Clear sex differences, irrespective of age, emerged in all visual and verbal tests, with females being more interested in infants than males. Male interest in infants remained fairly stable across the four age groups, whereas female interest in infants (...) was highest in childhood and adolescence and declined thereafter, particularly for the responses to visual stimuli. The observed developmental changes in female interest in infants are consistent with the hypothesis that they represent a biological adaptation for parenting. (shrink)

Sex is a fundamentally important biological variable. Recent years have seen significant progress in the integration of sex in many aspects of basic and clinical research, including analyses of sex differences in brain function. Significant advances in the technology available for studying the endocrine and nervous systems are now coupled with a more sophisticated awareness of the interconnections of these two communication systems of the body. A thorough understanding of the current knowledge, conceptual approaches, methodological capabilities, and challenges is (...) a prerequisite to continued progress in research and therapeutics in this interdisciplinary area. Sex Differences in the Brain provides scientists with the basic tools for investigating sex differences in brain and behavior and insight into areas where important progress in understanding physiologically relevant sex differences has already been made. This book was edited and co-authored by members of the Isis Fund Network on Sex, Gender, Drugs and the Brain, sponsored by the Society for Womens Health Research. The book is arranged in three parts. The first part of the book introduces the study of sex differences in the brain, with an overview of how the brain, stress systems, and pharmacogenetics differ in males and females and how this information is important for the study of behavior and neurobiology of both genders. The second part presents examples of sex differences in neurobiology and behavior from both basic and clinical research perspectives, covering both humans and nonhuman animals. The final part discusses sex differences in the neurobiology of disease and neurological disorders. For interested individuals as well as those who are considering conducting research at the intersections of endocrinology, neuroscience, and other areas of biomedicine, the study of sex differences offers exciting and challenging questions and perspectives. This book is intended as a guide and resource for clinicians, scientists, and students. (shrink)

In describing and explaining the sexes, medicine and science participated in the delineation of what was "feminine" and what was "masculine" in the Middle Ages. Hildegard of Bingen and Albertus Magnus, among others, writing about gynecology, the human constitution, fetal development, or the naturalistic dimensions of divine Creation, became increasingly interested in issues surrounding reproduction and sexuality. Did women as well as men produce procreative seed? How did the physiology of the sexes influence their healthy states and their susceptibility to (...) disease? Who derived more pleasure from sexual intercourse, men or women? The answers to such questions created a network of flexible concepts which did not endorse a single model of male-female relations, but did affect views on the health consequences of sexual abstinence for women and men and on the allocation of responsibility for infertility - problems with much social and religious significance in the Middle Ages. Sometimes at odds with, and sometimes in accord with other forces in medieval society, medicine and natural philosophy helped to construct a set of notions that divided significant portions of the world - from the behavior of animals to the operations of astrological signs - into "masculine" and "feminine." Even cases that seemed to exist outside the definitions of this duality, for example, hermaphrodite features or homosexual behavior, were brought under control by the application of gendered labels, such as "masculine women.". (shrink)

This commentary addresses the strength of the comparative approach to the study of sex differences in pain. Animal studies can focus our attention on mechanisms of sex differences in these clinical sex differences. Important sex differences are seen in descending pain modulation, thereby providing an explanation for the observation of sex differences in pain perception. [berkley].

Four issues relevant to sex differences in human aggression and violence are considered. (1) The motivation for play and serious aggression in children and juvenile animals is different. Consequently, the evolutionary explanations for each may be different. (2) Sex differences in intrasexual aggression may be due to effects of the attacker or the target. There is evidence that both males and females are more physically aggressive against males and less physically aggressive against females. The evolutionary explanation for each (...) component of the sex difference in intrasexual aggression may be different. (3) Aggression and violence are defined. The former is the attack, and the latter is the consequent injury or death. The evolutionary explanation for each may not be the same. (4) Most men and women are neither physically aggressive nor criminally violent. The evolutionary explanations of sex differences in aggression and violence should take this polymorphism into account. (shrink)

In this commentary, the microscopic animals of the genus Rotifera, or “rotifers,” emerge as a theory-provoking nonhuman animal. Rotifers embody otherness in ways that may intrigue scholars within both Human-Animal Studies and feminist science studies. In their encounter with rotifers, such fields of research might also engage each other in new, unexpected, and fruitful ways, as is here argued.

Going beyond the creolisation theories of Brathwaite and Glissant, I attempt to develop ideas concerning the gendering of creolisation, and a historicising of affects within it. Addressing affects as ‘physiological things’ contextualised in the history of the Caribbean slave plantation, I seek, importantly, to delineate a trajectory and development of a specific Creole history in relation to affects. Brathwaite's proposition that ‘the most significant (and lasting) inter-cultural creolisation took place’ within the ‘intimate’ space of ‘sexual relations’ is key to my (...) argument. In the light of this, I consider how Creole cultural knowledge about affect—as the primary motivational system inclusive of fear, anger, outrage and so on — might be identified, and what constitutes such Creole knowledge within which affect might be embedded. How might Glissant's relationality and Creole literary texts add to this knowledge? I focus primarily on three texts: Clarke's The Polished Hoe, Collins’ The Colour of Forgetting and Morejón's ‘Amo a mi amo’/‘l Love My Master’. Each text on which I draw is selected for its intersectional representation of gender relations, ‘knowledge about sexual difference’ and its representation of Creole subjectivities within the context problematised here as the ‘demonic ground’. Moreover, as auto-theorising texts, they represent both narrative and meta-narrative of a creolising of affects in and against the economy of the slave plantation. Each represents also a stage or aspect of the development of subjectivities and an affective community that inform this intervention concerned with theorising against consolidated, universalising and Eurocentric conceptualisations of affect. In the process, I attempt to offer a differentiated cartography and literary archaeology of affect. (shrink)

In this paper I examine Aristotle's account of sexual difference in Generation of Animals, arguing that Aristotle conceives of the production of males as the result of a successful teleological process, while he sees the production of females as due to material forces that defeat the norms of nature. My suggestion is that Aristotle endorses what I call the "degrees of perfection" model. I challenge Devin Henry's attempt to argue that Aristotle explains sex determination exclusively with reference to material necessity (...) (in particular, levels of "vital heat" in the male semen), for Aristotle's notion of "sufficient" or "deficient" vital heat is itself teleological. If, as Aristotle is aware, male and female embryos appear with approximately equal frequency in most species, how, in light of Physics II, can he conceive of the former as in accordance with nature, and the latter as somehow contrary to nature? My proposal is that Aristotle's notion of what happens usually (ως επì τò πoλυ) is bifurcated: the usual need not be more frequent. (shrink)

Sex, Gender, Ethics, and the Darwinian Evolution of Humanity examines the impact of Darwin's 'Descent of Man' on contemporary biology and the humanities. Its publication in 1871 was a founding event in anthropology. Its content was primarily concerned with the development of sexual life, social life, and intellectual life, not only as outcomes of evolution, but as components that have actively intermixed over time with the evolutionary mechanism of natural selection. The stamp of Darwinism on modern thought is still very (...) important and brings novelties to academic studies. Several fields influenced by Darwinian anthropology developed in recent decades, including evolutionary ethics, the evolution of sociality and sexual communication in animal and plant species. Sociobiology and evolutionary psychology are topics that draw heavily on Darwin's 'Descent of Man'. The understanding of Darwin's thought has also progressed greatly in recent decades, following the systematic study of Darwin's correspondence and notebooks, leading to a reassessment of the development of his thought on humans, social groups, and heredity, and how they come together in his theory of evolution. The book combines a historical perspective on Darwin's achievement and his legacy. It will be of interest to students and scholars in a variety of fields, from experimental biology to the social and historical sciences. (shrink)

Asking whether the sexes are natural kinds amounts to asking whether the categories, female and male, identify real divisions in nature, like the distinctions between biological species, or whether they mark merely artificial or arbitrary distinctions. The distinction between females and males in the animal kingdom is based on the relative size of the gametes they produce, with females producing larger gametes (ova) and males producing smaller gametes (sperm). This chapter argues that the properties of producing relatively large and (...) small gametes are causally correlated with a range of other properties in a wide variety of organisms, and this is what makes females and males natural kinds in the animal kingdom. The chapter concludes with a discussion of the relationship between sex and gender: while the difference between the sexes is biologically grounded, the difference between genders is socially based. Since gender depends in part on the perception of sex, whether or not gender is real or not does not depend on whether sex is, since social reality is constituted in part by our perceptions. The claim that sexes are natural kinds in the animal kingdom does not imply that the biological differences among female and male humans do and should have social consequences. (shrink)

Animal personality refers to the consistency of variation in behavior among individuals which may be the driving force behind variations in complex behaviors as well. Individual personality could predict how well an organism would perform in behavior and cognition related tasks, as well as survive and thrive in its environment. Therefore, we would expect inter-individual variations in many behaviors, which would persist even if habituation to the experimental setup occurs, which generally results in convergence of behavior. Our study used (...) wild-caught zebrafish from three natural habitats with differing ecological regimes, to understand how consistency and repeatability in specific traits such as boldness, exploration, and spatial ability varies across and within populations even when habituation causes change in behavior. We found that the extent of individual variation differs between populations, with dynamic habitats showing similar repeatability. This indicates that habitat conditions are important drivers of individual variation in addition to other factors, such as sex or size of individuals within populations. Although we found that sex and size played an important role within some populations for some behaviors, in others, the variation was likely caused by other factors, for which we have not accounted. This study underlines the importance of studying inter-individual differences as the phenomenon that underpins multiple behavioral traits and explains the possible role of environmental and inherent factors that drive these differences. (shrink)

In this paper, we argue that there are good, scientifically credible reasons for thinking that some nonhuman animals might have genders. We begin by considering why the sex/gender distinction has been important for feminist politics yet has also been difficult to maintain. We contrast contemporary views that trouble gender with those typical of traditional sex difference research, which has enjoyed considerable feminist critique, and argue that the anthropocentric focus of feminist accounts of gender weakens these critiques. Then, drawing from Jordan-Young’s (...) concept of gendered norms of reaction and van Anders’ Sexual Configurations Theory, we consider what it might mean to say that animals other than humans are gendered in a scientifically robust sense that does not simply reduce gender to sex or project human gender norms onto other animals. It is important that such an account is not only sensitive to its political ramifications for feminist and queer politics but is also sensitive to the ways in which troubling the human–nonhuman animal divide may seem to threaten those humans whose oppression is constituted by dehumanization and animalization. We suggest that, in fact, the contrary is true. We find that decolonial feminists have plausibly argued that animalizing oppression is premised on the human–animal divide and that the idea of nonhuman animal genders fits naturally with some traditional Indigenous ways of thinking about other animals and their relations with humans. (shrink)

It is widely accepted that valid consent is a necessary condition for permissible sexual activity. Since non-human animals, children, and individuals who are severely cognitively disabled, heavily intoxicated or unconscious, lack the cognitive capacity to give valid consent, this condition explains why it is impermissible to have sex with them. However, contrary to common intuitions, the same condition seems to render it impermissible to have sex with robots, for they too are incapable of consenting to sex due to insufficient cognitive (...) capacitation. This paper explores whether the intuition that non-consensual sex with robots is permissible can be vindicated, whilst preserving valid consent as a general requirement for permissible sexual activity. I develop and evaluate four possible ways to argue that there is a morally significant difference between robots on the one hand, and insufficiently cognitively capacitated humans and non-human animals on the other hand, to substantiate and justify the intuition that it is permissible to have non-consensual sex with the former but not with the latter. (shrink)

Biomedical and social scientists are increasingly calling the biological sex into question, arguing that sex is a graded spectrum rather than a binary trait. Leading science journals have been adopting this relativist view, thereby opposing fundamental biological facts. While we fully endorse efforts to create a more inclusive environment for gender‐diverse people, this does not require denying biological sex. On the contrary, the rejection of biological sex seems to be based on a lack of knowledge about evolution and it champions (...) species chauvinism, inasmuch as it imposes human identity notions on millions of other species. We argue that the biological definition of the sexes remains central to recognising the diversity of life. Humans with their unique combination of biological sex and gender are different from non‐human animals and plants in this respect. Denying the concept of biological sex, for whatever cause, ultimately erodes scientific progress and may open the flood gates to “alternative truths.”. (shrink)

On imagine trop souvent que les caractères " naturels " (le sexe, la race, par exemple) " tombent sous le sens ", sont des évidences inquestionnables. Tout au plus admet-on que les sociétés manipulent un peu tout cela, qu'il en résulte des différences, bonnes ou mauvaises, c'est selon... Pourtant, ne serait-ce pas déjà une manipulation que de prétendre certains caractères " naturels "? Le " naturel " ne serait-il pas une interprétation, bref un " artifice ", ancré dans de très (...) particulières relations sociales où certains sont assignés à l'état d'objet? Cet ouvrage associe la description d'une réalité matérielle quotidienne dans ses formes les plus banales (conversations de bistrot, scènes de rue, faits divers) et l'analyse précise des systèmes idéologiques qui prétendent expliquer cette réalité. (shrink)

This book is about how the systematic application of some basic principles of applied ethics yields some surprising and very unpopular results. In particular, Kershnar investigate three areas: sex, discrimination, and violence. The book argues that the following are some permissible in theory and practice. (1) Adult-child sex (2) Watching rape-pornography (3) State universities discriminating against women (4) The U.S. denying welfare to immigrants (5) Interrogational torture (6) Assassination In addition, the book argues that different races likely have different per (...) capita moral value and that equal opportunity is not valuable. These controversial conclusions will no doubt spur animated and thoughtful discussion amongst readers. (shrink)

Since the publication of The Sexual Politics of Meat in 1990, activist and writer Carol J. Adams (2000 [1990]) has put forth a feminist defence of veganism based on the argument that meat consumption and violence against animals are structurally related to violence against women, and especially to pornography and prostitution. Adams’ work has been influential in the growing fields of animal studies and posthumanism, where her research is frequently cited as the prime example of vegan feminism. However, her (...) particular radical feminist framework, including her anti-pornography and anti-prostitution arguments, are rarely acknowledged or critiqued. This article challenges the premises of Adams’ argument, demonstrating that her version of vegan feminism is based upon an unsubstantiated comparison between violence against women and violence against other-than-human animals, and on the silencing and exclusion of sex workers as subjects. The article contests the limited reading of Adams, and of feminism, offered in some key works in animal studies and posthumanism, at the same time that it recognises the need to challenge the anthropocentrism evident in much feminist theory. By way of alternative approaches to the sexual politics of veganism, the article highlights the interventions of artist and activist Mirha-Soleil Ross, proposing that her situated and embodied commitment to animal rights brings sex worker agency into the story, while resisting simple comparisons among different forms of violence. The concerns raised by Ross overlap in compelling ways with recent research in performance studies and labour history, bringing the question of work and workers, animal and human, to the fore. These studies point towards a potentially more useful framework than that of Adams for understanding the human violence suffered by different species, including those destined to be eaten by people. (shrink)

Different animal groups exhibit a surprisingly diversity of sex determination systems. Moreover, even systems that are superficially similar may utilize different underlying mechanisms. This diversity is illustrated by a comparison of sex determination in three well‐studied model organisms: the fruitfly Drosophila melanogaster, the nematode Caenorhabditis elegans, and the mouse. All three animals exhibit male heterogamety, extensive sexual dimorphism and sex chromosome dosage compensation, yet the molecular and cellular processes involved are now known to be quite unrelated. The similarities must (...) have arisen by convergent evolution. Studies of sex determination demonstrate that evolution can produce a variety of solutions to the same basic problems in development. (shrink)

It is argued that the question of whether or not one is required to be or become a strict vegetarian depends, not upon a rule or ideal that endorses vegetarianism on moral grounds, but rather upon whether one's own physical, biological nature is adapted to maintaining health and well-being on a vegetarian diet. Even if we accept the view that animals have rights, we still have no duty to make ourselves substantially worse off for the sake of other rights-holders. Moreover, (...) duties to others, such as fetuses and infants, may require one to consume meat or animal products. Seven classes of individuals who are not required to be or become vegetarians are identified and their examption is related to nutritional facts; these classes comprise most of the earth's population. The rule of vegetarianism defines a special or provisional duty rather than any general or universal rule, since its observance it based upon the biological capacities of individual humans whose genetic constitution and environment makes them suitably herbivorous. It is also argued that generalizing the vegetarian ideal as a social goal for all would be wrongful because it fails to consider the individual nutritional needs of humans at various stages of life, according to biological differences between the sexes, and because it would have the eugenic effect of limiting the adaptability of the human species. The appeal to the natural interests of omnivores will not justify any claim that humans may eat amounts of meat or animal products in excess of a reasonable safety margin since animals have rights-claims against us. (shrink)

It is argued that the question of whether or not one is required to be or become a strict vegetarian depends, not upon a rule or ideal that endorses vegetarianism on moral grounds, but rather upon whether one's own physical, biological nature is adapted to maintaining health and well-being on a vegetarian diet. Even if we accept the view that animals have rights, we still have no duty to make ourselves substantially worse off for the sake of other rights-holders. Moreover, (...) duties to others, such as fetuses and infants, may require one to consume meat or animal products. Seven classes of individuals who are not required to be or become vegetarians are identified and their examption is related to nutritional facts; these classes comprise most of the earth's population. The rule of vegetarianism defines a special or provisional duty rather than any general or universal rule, since its observance it based upon the biological capacities of individual humans whose genetic constitution and environment makes them suitably herbivorous. It is also argued that generalizing the vegetarian ideal as a social goal for all would be wrongful because it fails to consider the individual nutritional needs of humans at various stages of life, according to biological differences between the sexes, and because it would have the eugenic effect of limiting the adaptability of the human species. The appeal to the natural interests of omnivores will not justify any claim that humans may eat amounts of meat or animal products in excess of a reasonable safety margin since animals have rights-claims against us. (shrink)

The past decade has seen an increase in interest relating to the correlates and determinants of attitudes about nonhuman animals, especially attitudes about the use or abuse of animals. However, little research has explicitly addressed individual differences in attitudes about the neglect of animals. The current study employs a factor-analytic approach to explore whether attitudes about animal neglect can be reliably differentiated from attitudes about animal abuse and whether the relationship between attitudes about animal neglect and (...) animal abuse differs as a function of gender. Results indicated that attitudes about abuse and neglect can be reliably differentiated among both men and women. However, the structure of these attitudes appears to differ substantially by sex. This paper discusses theoretical and practical implications of these results. (shrink)

John Dupré explores the ways in which we categorize animals, including humans, and comes to refreshingly radical conclusions. He opposes the idea that there is only one legitimate way of classifying things in the natural world, the 'scientific' way. The lesson we should learn from Darwin is to reject the idea that each organism has an essence that determines its necessary place in the unique hierarchy of things. Nature is not like that: it is not organized in a single system. (...) For instance, there is no universal principle by which organisms can be sorted into species. We are obliged to accept that different classificatory schemes are equally valid, and to take a pluralistic view of biology and the human sciences. These provocative and readable essays move on to discuss a set of contentious topics relating to human nature. To start with, Dupré argues that the concept of a universal human nature should be rejected. He questions the relevance of evolution to explanation of human behaviour, and casts doubt on the concept of normality in human behaviour. He shows that misunderstanding of biology and evolution has lead to widespread misconceptions about human sex and gender-in particular, about sexual behaviour and gender roles. The books concludes with a pair of essays about the differences between humans and animals, which may not be quite so clear-cut as we think. (shrink)

The origin and progress of multicellularity, which is one of the crucial steps in the evolution of life, remains unclear and stringent phylogenetic reconstruction of the process is difficult. However, further theoretical considerations of the problem could be useful for the creation of a verifiable hypothesis. Sex as a ubiquitous biological phenomenon is usually considered as something entirely linked with reproduction. This is mostly true for modem multicellular organisms, but at the earliest stage of evolution of eukaryotes it was not (...) so. At that time the sexual process had nothing to do with reproduction, and only later, sex and reproduction merged together.One of the aims of this paper is to consider the sexual process as a likely basis for the establishment of multicellularity and to discuss the early stages of evolution of the multicellularity from this perspective. It is suggested that mitotic reproduction of cells at different stages of the sexual cycle of unicellular ancestors might be the starting points for independent transition to multicellularity in different taxa. Numerous consequences of these transitions, including evolution of bisexuality and development of novel meiotic functions in animals, are discussed. (shrink)

The pathway that controls sexual fate in the nematode Caenorhabditis elegans has been well characterized at the molecular level. By identifying differences between the sex‐determination mechanisms in C. elegans and other nematode species, it should be possible to understand how complex sex‐determining pathways evolve. Towards this goal, orthologues of many of the C. elegans sex regulators have been isolated from other members of the genus Caenorhabditis. Rapid sequence evolution is observed in every case, but several of the orthologues appear (...) to have conserved sex‐determining roles. Thus extensive sequence divergence does not necessarily coincide with changes in pathway structure, although the same forces may contribute to both. This review summarizes recent findings and, with reference to results from other animals, offers explanations for why sex‐determining genes and pathways appear to be evolving rapidly. Experimental strategies that hold promise for illuminating pathway differences between nematodes are also discussed. BioEssays 25: 221–231, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

Navigating to goal locations in a known environment (wayfinding) can be accomplished by different strategies, notably by taking habitual, well-learned routes (response strategy) or by inferring novel paths, such as shortcuts, from spatial knowledge of the environment's layout (place strategy). Human and animal neuroscience studies reveal that these strategies reflect different brain systems, with response strategies relying more on activation of the striatum and place strategies associated with activation of the hippocampus. In addition to individual differences in strategy, (...) recent behavioral studies show sex differences such that men use place strategies more than women, and age differences such that older adults use more response strategies than younger adults. This paper takes a comprehensive multilevel approach to understanding these differences, characterizing wayfinding as a complex information processing task. This analysis reveals factors that affect navigation strategy, including availability of the relevant type of environmental knowledge, momentary access to this knowledge, trade-offs between physical and mental effort in different navigation contexts, and risk taking. We consider how strategies are influenced by the computational demands of a navigation task and by factors that affect the neural circuits underlying navigation. We also discuss limitations of laboratory studies to date and outline priorities for future research, including relating wayfinding strategies to independent measures of spatial knowledge, and studying wayfinding strategies in naturalistic environments. (shrink)

Navigating to goal locations in a known environment (wayfinding) can be accomplished by different strategies, notably by taking habitual, well-learned routes (response strategy) or by inferring novel paths, such as shortcuts, from spatial knowledge of the environment's layout (place strategy). Human and animal neuroscience studies reveal that these strategies reflect different brain systems, with response strategies relying more on activation of the striatum and place strategies associated with activation of the hippocampus. In addition to individual differences in strategy, (...) recent behavioral studies show sex differences such that men use place strategies more than women, and age differences such that older adults use more response strategies than younger adults. This paper takes a comprehensive multilevel approach to understanding these differences, characterizing wayfinding as a complex information processing task. This analysis reveals factors that affect navigation strategy, including availability of the relevant type of environmental knowledge, momentary access to this knowledge, trade-offs between physical and mental effort in different navigation contexts, and risk taking. We consider how strategies are influenced by the computational demands of a navigation task and by factors that affect the neural circuits underlying navigation. We also discuss limitations of laboratory studies to date and outline priorities for future research, including relating wayfinding strategies to independent measures of spatial knowledge, and studying wayfinding strategies in naturalistic environments. (shrink)

Different animal groups exhibit a surprisingly diversity of sex determination systems. Moreover, even systems that are superficially similar may utilize different underlying mechanisms. This diversity is illustrated by a comparison of sex determination in three well‐studied model organisms: the fruitfly Drosophila melanogaster, the nematode Caenorhabditis elegans, and the mouse. All three animals exhibit male heterogamety, extensive sexual dimorphism and sex chromosome dosage compensation, yet the molecular and cellular processes involved are now known to be quite unrelated. The similarities must (...) have arisen by convergent evolution. Studies of sex determination demonstrate that evolution can produce a variety of solutions to the same basic problems in development. (shrink)

The concept of animal personality is based on consistent individual differences in behaviour, yet little is known about the factors responsible for such variation. Theory based on sex-specific selection predicts sexual dimorphism in personality-related traits and, in some cases, differences in trait variances between the sexes. In this study, we examined the sources of individual variation for boldness behaviour in guppies (Poecilia reticulata). We first demonstrated heightened boldness expression in males relative to females across feral wild types, (...) artificially selected domestic ‘designer’ guppies, and putative hybrids of the two. Boldness and body size covaried at the strain level but were not associated among individuals within strains. We also found high and repeatable behavioural differences among individuals (0.40 > intraclass r > 0.60) in all sex/strain groups except hybrid strain females. However, there was no evidence for the heightened inter-individual male variance anticipated for personality traits subject to certain forms of directional sex-specific selection. Domestic fish were boldest overall, and indicated the largest sex difference, which is consistent with genetic linkage between boldness and male ornamental colouration. Consistently high intrinsic variation in boldness behaviour, which extends to inbred domesticated fish, may in part underpin the invasive potential of this species. (shrink)

Sex is probably the best example of stable biological variation within the human species. Scientists have tried to account for the origin of sex differences in biological terms using evolutionary theory. Although Charles Darwin derived his theories of natural and sexual selection with no consideration for sex, he assumed that the differences he observed in male and female human and animal behavior were variations related to biology. This chapter examines the link between sex and evolution by reflecting (...) on the various resonances between cultural and social norms one the one hand, and biological theory on the other. It first considers scientific explanations of women's nature, or womanhood as a subject of science, before turning to research on female choice and the animal/woman divide in the early twentieth century. The chapter also discusses the use of human and animal models of “natural” sexual behavior after World War II, sexual selection and biological determinism in the 1970s, and efforts to bridge the gap between feminism and evolutionary theory. (shrink)

If we are going to treat other species so very differently from our own — killing, eating and experimenting on pigs and sheep, for example, but never human beings — then it seems we need to come up with some morally relevant difference between us and them that justifies this difference in treatment. Otherwise it appears we are guilty of bigotry (in just the same way that someone who discriminates on the basis of race or sex is guilty of bigotry). (...) But what is this morally relevant difference? Julia Tanner's article examines, and rejects, some of the most popular answers to this question. -/- . (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)

Several hundred thousand intellectually talented 12-to 13-year-olds have been tested nationwide over the past 16 years with the mathematics and verbal sections of the Scholastic Aptitude Test (SAT). Although no sex differences in verbal ability have been found, there have been consistent sex differences favoring males in mathematical reasoning ability, as measured by the mathematics section of the SAT (SAT-M). These differences are most pronounced at the highest levels of mathematical reasoning, they are stable over time, and (...) they are observed in other countries as well. The sex difference in mathematical reasoning ability can predict subsequent sex differences in achievement in mathematics and science and is therefore of practical importance. To date a primarily environmental explanation for the difference in ability has not received support from the numerous studies conducted over many years by the staff of Study of Mathematically Precocious Youth (SMPY) and others. We have studied some of the classical environmental hypotheses: attitudes toward mathematics, perceived usefulness of mathematics, confidence, expectations/ encouragement from parents and others, sex-typing, and differential course-taking. In addition, several physiological correlates of extremely high mathematical reasoning ability have been identified (left-handedness, allergies, myopia, and perhaps bilateral representation of cognitive functions and prenatal hormonal exposure). It is therefore proposed that the sex difference in SAT-M scores among intellectually talented students, which may be related to greater male variability, results from both environmental and biological factors. (shrink)

Several themes in this issue of the Hastings Center Report deserve mention. Entirely fortuitously, several shorter pieces in this issue discuss the nature of the doctor‐patient relationship and the need for physicians to engage patients personally rather than only technically. Also, a special supplement to this issue addresses the shifting terrain of the debate about the use of animals in medical research. Perhaps the most prominent topic in the issue, however, is the physical modification of women's genitals. Both articles address (...) this topic, and though there are significant differences between the two articles, both circle specifically around the question of whether the modification of women's genitals may be driven by cultural norms of womanhood and how women differ from men, and both comment not just on the questions but on the social debate about them. (shrink)

This article utilizes three premises. There are commonly ecologically oriented, naturally selected specialized differences in frequency and/or quality as well as sexually selected differences between the sexes. Sex in the sense of coming together and going apart or going apart and coming together is trade in these naturally selected differences, i.e., there is a mating market in sexual species. While such trade is beneficial to the population as a whole, sexual competition and selection is conflict over the (...) profits of that trade and can be detrimental to the population as a whole. These premises yield a naturally selected sex allocation theory of the possible directions and forms of sexual selection, i.e., one that includes costs as well as frequencies. This can explain conventional sex roles, the sex-role reversed, inter- as well as intrasexual selection, and passive as well as active choice. Any of these alternatives may be over mates, over gametes, or both. A hypothetical example based on density dependence relative to resources is provided, one that suggests that centrioles may be a cytoplasmic resource in males in multicellular animals, and which are the target of active choice and the mechanism of manipulation in passive female choice. As a whole, the approach yields a truly general theory of sexual selection, provides an alternative to the mechanism for Fisher’s principle, and gives a theoretical explanation for Mayr’s biological species definition. (shrink)

Trois débats nous obsèdent : autour du genre, des droits de l'animal, de l'euthanasie. Et trois disciplines politiquement correctes traitent désormais de ces questions dans le monde universitaire : gender studies, animal studies, bioéthique. Cependant, lorsqu'on lit les textes des fondateurs de ces disciplines, John Money, Judith Butler, Peter Singer, Donna Haraway et quelques autres, on s'aperçoit que, derrière les bons sentiments affichés, se font jour des conséquences absurdes sinon abjectes. Si le genre n'est pas lié au sexe, (...) pourquoi ne pas en changer tous les matins? Si le corps est à la disposition de notre conscience, pourquoi ne pas le modifier à l'infini? S'il n'y a pas de différence entre animaux et humains, pourquoi ne pas faire des expériences scientifiques sur les comateux plutôt que sur les animaux? Pourquoi ne pas avoir de relations sexuelles avec son chien, voire l'épouser? S'il est des vies dignes d'être vécues et d'autres qui ne le sont pas, pourquoi ne pas liquider les " infirmes ", y compris les enfants " défectueux "? Pourquoi ne pas nationaliser les organes des quasi-morts au profit d'humains plus prometteurs? Jean-François Braunstein a mené un travail considérable et novateur : il a lu les milliers de pages de ces penseurs célébrés dans le monde occidental ; il revient sur leurs idées, leurs contradictions, leur parcours personnel ; il analyse, souligne, contredit, déconstruit. L'erreur consiste à vouloir " effacer les limites " : entre les sexes, entre les animaux et les humains, entre les vivants et les morts. Il convient, au contraire, d'affronter ces limites qui nous constituent. Oui, parfois la philosophie devient folle, quand elle oublie l'homme. (shrink)

Dual functional brain asymmetry refers to the notion that in most individuals the left cerebral hemisphere is specialized for language functions, whereas the right cerebral hemisphere is more important than the left for the perception, construction, and recall of stimuli that are difficult to verbalize. In the last twenty years there have been scattered reports of sex differences in degree of hemispheric specialization. This review provides a critical framework within which two related topics are discussed: Do meaningful sex (...) class='Hi'>differences in verbal or spatial cerebral lateralization exist? and, if so, Is the brain of one sex more symmetrically organized than the other? Data gathered on right-handed adults are examined from clinical studies of patients with unilateral brain lesions; from dichotic listening, tachistoscopic, and sensorimotor studies of functional asymmetries in non-brain-damaged subjects; from anatomical and electrophysiological investigations, as well as from the developmental literature. Retrospective and descriptive findings predominate over prospective and experimental methodologies. Nevertheless, there is an impressive accummulation of evidence suggesting that the male brain may be more asymmetrically organized than the female brain, both for verbal and nonverbal functions. These trends are rarely found in childhood but are often significant in the mature organism. (shrink)

Women have consistently higher levels of disgust than men. This sex difference is substantial in magnitude, highly replicable, emerges with diverse assessment methods, and affects a wide array of outcomes—including job selection, mate choice, food aversions, and psychological disorders. Despite the importance of this far-reaching sex difference, sound theoretical explanations have lagged behind the empirical discoveries. In this article, we focus on the evolutionary-functional level of analysis, outlining hypotheses capable of explaining why women have higher levels of disgust than men. (...) We present four hypotheses for sexual disgust and six for pathogen disgust, along with testable predictions. Discussion focuses on additional new hypotheses and on future research capable of adjudicating among these competing, but not mutually exclusive, hypotheses. (shrink)

The signal for sex determination in the nematode Caenorhabditis elegans is the ratio between the number of × chromosomes and the number of sets of autosomes (the X/A ratio). Animals with an X/A ratio of 0.67 (a triploid with two × chromosomes) or less are males. Animals with an X/A ratio of 0.75 or more are hermaphrodites. Thus, diploid males have one × chromosome and diploid hermaphrodites have two × chromosomes. However, the difference in X‐chromosome number between the sexes is (...) not reflected in general levels of X‐linked gene expression because of the phenomenon of dosage compensation. In dosage compensation, X‐linked gene expression appears to be ‘turned down’ in 2X animals to the 1X level of expression. An intriguing and unexplained finding is that mutations and X‐chromosome duplications that elevate X‐linked gene expression also feminize triploid males. One way that this relationship between sex determination and X‐linked gene expression may be operating is discussed. (shrink)

ABSTRACT In our current moment, there is considerable interest in networks, in how people and things are connected. This essay outlines one approach that brings together insights from actor-network theory, social network analysis, and digital history to interpret past scientific activity. Multispecies network analysis (MNA) is a means of understanding the historical interactions among scientists, institutions, and preferred experimental animals. A reexamination of studies of sexual behavior funded by the Committee for Research in Problems of Sex between the 1920s and (...) the 1940s demonstrates the applicability of MNA to clarifying the relations that sustained this area of psychology. The measures of weighted degree and betweenness can highlight which nodes (whether organisms or institutions) were particularly “central” to this network. Rats featured as the animals most widely studied during this period, but the analysis also reveals distinct institutional and disciplinary cultures where different species were favored as either surrogates for humans or representatives of more general biological groups. (shrink)

Despite the importance of extrapair copulation (EPC) in human evolution, almost nothing is known about the design features of EPC detection mechanisms. We tested for sex differences in EPC inference-making mechanisms in a sample of 203 young couples. Men made more accurate inferences (φmen = 0.66, φwomen = 0.46), and the ratio of positive errors to negative errors was higher for men than for women (1.22 vs. 0.18). Since some may have been reluctant to admit EPC behavior, we modeled (...) how underreporting could have influenced these results. These analyses indicated that it would take highly sex-differentiated levels of underreporting by subjects with trusting partners for there to be no real sex difference. Further analyses indicated that men may be less willing to harbor unresolved suspicions about their partners’ EPC behavior, which may explain the sex difference in accuracy. Finally, we estimated that women underreported their own EPC behavior (10%) more than men (0%). (shrink)

Are there sex differences in pain? For experimentally delivered somatic stimuli, females have lower thresholds, greater ability to discriminate, higher pain ratings, and less tolerance of noxious stimuli than males. These differences, however, are small, exist only for certain forms of stimulation and are affected by many situational variables such as presence of disease, experimental setting, and even nutritive status. For endogenous pains, women report more multiple pains in more body regions than men. With no obvious underlying rationale, (...) some painful diseases are more prevalent among females, others among males and, for many diseases, symptoms differ between females and males. Sex differences in attitudes exist that affect not only reporting, coping, and responses to treatment, but also measurement and treatment. So many variables are operative, however, that the most striking feature of sex differences in reported pain experience is the apparent overall lack of them. On the other hand, deduction from known biological sex differences suggests that these are powerful sex differences in the operation of pain mechanisms. First, the vaginal canal provides an additional route in women for internal trauma and invasion by pathological agents that puts them at greater risk for developing hyperalgesia in multiple body regions. Second, sex differences in temporal patterns are likely to give rise to sex differences in how pain is and stimuli are interpreted, a situation that could lead to a greater variability and wider range of pains without obvious peripheral pathology among females. Third, sex differences in the actions of sex hormones suggest pain-relevant differences in the operation of many neuroactive agents, opiate and nonopiate systems, nerve growth factor, and the sympathetic system. Thus, while inductive analysis of existing data demonstrate more similarities than differences in pain experience between females and males, deductive analysis suggests important operational sex differences in its production. (shrink)

Lars von Trier’s Antichrist (2009) has often been described as a ‘gothic’, if not straightforwardly ‘horror’ movie. While this claim could easily be challenged with regard to strict genre definitions, it is doubtless the case that the film deals very explicitly with fear, first and foremost the female protagonist’s fear of herself, which is placed at the top of the so-called ‘pyramid of fear’ drawn by her therapist/wanna-be-Saviour partner. My opinion is that Antichrist perfectly displays the horrific effects of the (...) direct embodiment, following a true love encounter, of the symbolic positions which Lacan associated with male and female sexuation. If human sexuality relies on the logic for which there is only one mythical man who is truly whole while every real woman is not wholly whole, what happens when He and She (the nameless protagonists of the movie) fully identify with such irreducible asymmetry between the sexes, its fundamental derailment from nature? They short-circuit the material singularity of a specific human animal with the abstract universality of gender. With the same move, they cannot overcome (or sublimate) the realisation that, in the female protagonist’s own words, woman is ‘evil’ – as long as she feels guilty of what man accuses her – and man is a ‘bastard’ – haunted by the phantasm of unifying purity which woman disrupts. Gynocide as male totalizing extermination of universal difference and genital self-mutilation as female reflexive hatred for the supposedly exceptional man mark the sadomasochistic extremes of the scene of the not-two, the frightening ob-scenity ( o-skené ), or off-representation, of human sexuality. (shrink)

Aristotle's remarks about the differences between the sexes have become infamous for their implications for the social status of women. In his observations on female biology, Aristotle claims that "the female nature is, as it were, a deformity." In describing women's role in the public sphere, he claims that women are naturally subordinate because, while they possess a deliberative faculty, that capacity is "without authority." While both claims express the "inferiority" of female bodies/women relative to male bodies/men, it is (...) not self-evident that the defects Aristotle identifies in female biology have cognitive or moral manifestations that would justify the rule of men over women in political life. Marguerite Deslauriers here aims to construct a coherent picture of Aristotle's views on sexual and gender-based difference from these remarks and to show the extent to which his views on female biology and women's role in politics are causally connected. Without exculpating Aristotle from charges of misogyny, Deslauriers contextualizes his explanations of the role and origin of female animals in his biology and the role of women in his political philosophy; she shows how Aristotle developed these views and the importance they hold for his wider philosophical commitments. She then explores how Aristotle might have seen the link between the physiology of sex and the bearing it has on political life. She ultimately argues that in Aristotle's conception of sexual difference in biology and politics, there is a tension between his view of the inferiority of female bodies and women and his commitment to the idea that females and women are valuable both for generation and for the political life characteristic of human beings. In this tension she finds a difference between Aristotle and his predecessors: while previous accounts associate sexual difference with affliction, Aristotle sees sexual difference as a benefit, both to a species and a political community. This volume will be of interest to philosophers and students interested in ancient philosophy, feminist philosophy, as well as those studying moral and political philosophy. (shrink)

Benenson et al. postulate that human females evolved unique survival adaptations to facilitate maternal and grandmaternal care. This hypothesis is consistent with the broader hypothesis that female phenotypes are more ecologically optimal, but further evidence is needed to make a compelling case that sex differences in self-protection are not primarily the result of more intense sexual selection on males.