I argue that the magnitude and nature of sex differences in aggression, their development, causation, and variability, can be better explained by sexualselection than by the alternative biosocial version of social role theory. Thus, sex differences in physical aggression increase with the degree of risk, occur early in life, peak in young adulthood, and are likely to be mediated by greater male impulsiveness, and greater female fear of physical danger. Male variability in physical aggression is consistent with (...) an alternative life history perspective, and context-dependent variability with responses to reproductive competition, although some variability follows the internal and external influences of social roles. Other sex differences, in variance in reproductive output, threat displays, size and strength, maturation rates, and mortality and conception rates, all indicate that male aggression is part of a sexually selected adaptive complex. Physical aggression between partners can be explained using different evolutionary principles, arising from the conflicts of interest between males and females entering a reproductive alliance, combined with variability following differences in societal gender roles. In this case, social roles are particularly important since they enable both the relatively equality in physical aggression between partners from Western nations, and the considerable cross-national variability, to be explained. (shrink)
In Darwin’s Sacred Cause, Adrian Desmond and James Moore contend that “Darwin would put his utmost into sexualselection because the subject intrigued him, no doubt, but also for a deeper reason: the theory vindicated his lifelong commitment to human brotherhood”. Without questioning Desmond and Moore’s evidence, I will raise some puzzles for their view. I will show that attention to the structure of Darwin’s arguments in the Descent of Man shows that they are far from straightforward. As (...) Desmond and Moore note, Darwin seems to have intended sexualselection in non-human animals to serve as evidence for sexualselection in humans. However, Darwin’s account of sexualselection in humans was different from the canonical cases that Darwin described at great length. If explaining the origin of human races was the main reason for introducing sexualselection, and if sexualselection was a key piece of Darwin’s anti-slavery arguments, then it is puzzling why Darwin would have spent so much time discussing cases that did not really support his argument for the origin of human races, and it is also puzzling that his argument for the origin of human races would be so poor. (shrink)
We report three studies which test a sexualselection hypothesis for male war heroism. Based on evolutionary theories of mate choice we hypothesize that men signal their fitness through displaying heroism in combat. First, we report the results of an archival study on US-American soldiers who fought in World War II. We compare proxies for reproductive success between a control sample of 449 regular veterans and 123 surviving Medal of Honor recipients of WWII. Results suggest that the heroes (...) sired more offspring than the regular veterans. Supporting a causal link between war heroism and mating success, we then report the results of two experimental studies. We find evidence that female participants specifically regard men more sexually attractive if they are war heroes. This effect is absent for male participants judging female war heroes, suggesting that bravery in war is a gender specific signal. Finally, we discuss possible implications of our results. (shrink)
Sexualselection processes have received much attention in recent years, attention reflected in interest in human mate preferences. Among these mate preferences are preferences for physical attractiveness. Preferences in and of themselves, however, do not fully explain the nature of the relationships that individuals attain. A tacit negotiation process underlies relationship formation and maintenance. The notion that preferences for physical attractiveness evolved under parasite-driven “good genes” sexualselection leads to predictions about the nature of trade-offs that (...) individuals make between mates’ physical attractiveness and investment potential. These predictions and relevant data are explored, with a primary emphasis on women’s preferences for men’s qualities. In addition, further implications of trade-offs are examined, most notably (a) the impact of environmental variations on the nature of mating and (b) some effects of trade-offs on infidelity and male attempts to control women. (shrink)
The fitness of a eukaryote hinges on the coordinated function of the products of its nuclear and mitochondrial genomes in achieving oxidative phosphorylation. I propose that sexualselection plays a key role in the maintenance of mitonuclear coadaptation across generations because it enables pre-zygotic sorting for coadapted mitonuclear genotypes. At each new generation, sexual reproduction creates new combinations of nuclear and mitochondrial genes, and the potential arises for mitonuclear incompatibilities and reduced fitness. In reviewing the literature, I (...) hypothesize that individuals engaged in mate choice select partners with correct species-typical mitochondrial and nuclear genotypes as well as individuals with highly functional cellular respiration. The implication is that mate choice for compatible nuclear and mitochondrial genes can play a significant role in generating the patterns of ornamentation and preferences observed in animals. A number of testable predictions emerge from this mitonuclear compatibility hypothesis of sexualselection. Products of mitochondrial and nuclear genes co-function to enable cellular respiration, so it is critical that compatible mitochondrial and nuclear genes be matched each generation. I propose that a core function of mate choice is selection for mitochondrial and nuclear genes that create compatible and functional combinations in offspring. (shrink)
Recently Geoffrey Miller has suggested that humor evolved through sexualselection as a signal of "creativity," which in turn implies youthfulness, intelligence, and adaptive unpredictability. Drawing upon available empirical studies, I argue that the evidence for a link between humor and creativity is weak and ambiguous. I also find only tenuous support for Miller’s assumption that the attractiveness of the "sense of humor" is to be found in the wittiness of its possessor, since those who use the phrase (...) often seem to associate it with the affects of relatively mirthless "bonding" laughter. Humor, I conclude, may have evolved as an instrument for achieving broad social adhesiveness and for facilitating the individual’s maneuverability within the group, but that it evolved through sexualselection has yet to be convincingly demonstrated. (shrink)
This essay traces the interlinked origins of two concepts found in Charles Darwin's writings: "unconscious selection," and sexualselection as applied to humanity's anatomical race distinctions. Unconscious selection constituted a significant elaboration of Darwin's artificial selection analogy. As originally conceived in his theoretical notebooks, that analogy had focused exclusively on what Darwin later would call "methodical selection," the calculated production of desired changes in domestic breeds. By contrast, unconscious selection produced its results unintentionally (...) and at a much slower pace. Inspiration for this concept likely came from Darwin's early reading of works on both animal breeding and physical ethnology. Texts in these fields described the slow and unplanned divergence of anatomical types, whether animal or human, under the guidance of contrasting ideals of physical perfection. These readings, it is argued, also led Darwin to his theory of sexualselection as applied to race, a theme he discussed mainly in his book The Descent of Man (1871). There Darwin described how the racial version of sexualselection operated on the same principle as unconscious selection. He thereby effectively reunited these kindred concepts. (shrink)
Turtles are among the most intriguing amniotes but their communication and signaling have rarely been studied. Traditionally, they have been seen as basically just silent armored ‘walking stones’ with complex physiology but no altruism, maternal care, or aesthetic perception. Recently, however, we have witnessed a radical change in the perception of turtle behavioral and cognitive skills. In our study, we start by reviewing some recent findings pertaining to various highly developed behavioral and cognitive patterns with special emphasis on turtles. Then (...) we focus on freshwater turtles and use data about their sexual behavior and size sexual dimorphism to test whether conspicuous coloration of the head is in these animals related to sexual processes. We found that absence of aggressive mating behavior is statistically associated with the presence of conspicuous coloration on turtles’ heads. It also seems that while species with female-biased SSD are characterised by conspicuously colored head ornaments, in species with male-biased SSD conspicuous coloration is absent. Unlike large females, males thus seem to be under pressure to develop conspicuous coloration and engage in non-aggressive behavior using signaling to succeed in courtship. And finally, we discuss possible roles of head color patterns in turtle communication during mating. (shrink)
The capacity to engage with art is a human universal present in all cultures and just about every individual human. This indicates that this capacity is evolved. In this Critical Notice of Denis Dutton's The Art Instinct, I discuss various evolutionary scenarios and their consequences. Dutton and I both reject the "spandrel" approach that originates from the work of Gould and Lewontin. Dutton proposes, following work of Geoffrey Miller, that art is sexually selected--that art-production is a sign of a fit (...) genome in males. I argue that while assortative mating may well have had a role in the evolution of "the art instinct", group selection is a better explanation. I also take issue with Dutton's "cluster concept" approach to defining art, and argue that it is a universal and essential characteristic of art that it is appreciated both for what it expresses and for the way that it expresses. It thus requires a reflexive capacity that is not operative in the appreciation of sport spectacles and pornography. (shrink)
The evolution of human language, and the kind of thought the communication of which requires it, raises considerable explanatory challenges. These systems of representation constitute a radical discontinuity in the natural world. Even species closely related to our own appear incapable of either thought or talk with the recursive structure, generalized systematicity, and task-domain neutrality that characterize human talk and the thought it expresses. W. Tecumseh Fitch’s proposal (2004, in press) that human language is descended from a sexually selected, prosodic (...) proto-language that approximated its syntactic complexity, and later acquired semantics thanks to kin selection for its use as a means of pedagogical transmission, has the promise of meeting these explanatory challenges. However, Fitch’s theory raises two problems of its own: (1) according to Boyd and Richerson (1996, Proc. Br. Acad. 88: 77–93), circumstances in which pedagogy is adaptive are inevitably rare in nature, and (2) it is unlikely that our non-discursive precursors had generally systematic, task-domain neutral thoughts to communicate to their offspring. I propose solutions to these problems. Pedagogy would be favored in a population where complex rituals dominated diverse aspects of life. Prosodic proto-language could emerge as the medium of pedagogic transmission. As this medium was used to teach a greater variety of tasks, it would become increasingly general and domain neutral. The presence and importance of such a system of communication in hominid populations could then drive, via Baldwinian mechanisms, the evolution of a kind of ‘thinking for speaking’ (Slobin 1991, Pragmatics 1: 7–25) characterized by recursive structure, generalized systematicity, and task-domain neutrality. (shrink)
I discuss the ubiquity of power law distributions in language organisation (and elsewhere), and argue against Miller’s (The mating mind: How sexual choice shaped the evolution of human nature, William Heinemann, London, 2000) argument that large vocabulary size is a consequence of sexualselection. Instead I argue that power law distributions are evidence that languages are best modelled as dynamical systems but raise some issues for models of iterated language learning.
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 sexualselection, 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 sexualselection, provides an alternative to the mechanism for Fisher’s principle, and gives a theoretical explanation for Mayr’s biological species definition. (shrink)
One of the explicit objectives of Darwin's Descent of Man, and Selection in Relation to Sex was to explain cultural differences seen in human beings. Such an explanation, Darwin believed, was to rest upon an understanding of sexualselection. I examine the role that the beautiful plays within the mechanism of sexualselection as it works to differentiate isolated groups. It is suggested that an examination of the relationship between sexualselection and artificial (...)selection — a relationship mediated by the beautiful — will illuminate key issues of the Descent as well as contemporary debates regarding the relationship between evolution and ethics. The beautiful, originally rooted in sexualselection, can become de-coupled from sexualselection and utilized in some selective process which is conscious. (shrink)
The importance of mate choice and sexualselection has been emphasized by the majority of evolutionary psychologists. This paper assesses three cases of work on mate choice and sexualselection in evolutionary psychology: David Buss on cross-cultural human mate preferences, Randy Thornhill and Steve Gangestad on the link between mate preferences and fluctuating asymmetry, and Geoffrey Miller on the role of Fisher’s runaway process in human evolution. A mixture of conceptual and empirical problems in each case (...) highlights the general weakness of work in evolutionary psychology on these issues. (shrink)
Textbooks provide a rich site within which to investigate how members of a scientific discipline choose to represent their research to general audiences. We used critical contextual empiricism as a framework for interrogating how a scientific community is depicted via images in evolution textbook chapters on sexualselection. Textbooks that exhibit science within the tenets of critical contextual empiricism will depict uptake of disciplinary change and acknowledge the inseparability of the social and rational aspects of scientific knowledge construction. (...)Sexualselection is an exemplary arena for this work because the field has undergone substantial change in the past few decades that has been driven by critique from within and among disciplines. We used quantitative methods and content analysis to examine images from the textbook editions and from a time series of editions to examine the portrayal of updated understandings of sexualselection. We found that most textbook images did not reflect the shift happening in the scientific community. Images highlighted primarily the classic view of sexualselection focused on males. Examples typical of a more realistic, complicated understanding received little attention even though the scientific literature on these topics appeared decades before these textbooks were published. Images of males were more common than images of females, females were depicted for fewer concepts than males, and images of males and females reinforced stereotypical sex roles. This study highlights an opportunity for acknowledging the inseparability of the social and the rational in scientific knowledge construction. (shrink)
Sexualselection traditionally involves male-male competition and female choice, but in some species, including humans, sexualselection can also involve female-female competition and male choice. The degree to which one aspect of sexualselection or another is manifest in human populations will be influenced by a host of social and ecological variables, including the operational sex ratio. These variables are discussed in connection with the relative contribution of sexualselection and the division (...) of labor to the evolution of human sex differences. (shrink)
Archer recognizes that sexualselection theory is sensitive to the effects of ecologies on sex differences, yet he does not explain the impact of such variation. For example, to what degree are there sex differences in aggression in polygynous and monogamous societies? I demonstrate how differences in mating perceptions affect the traditional dichotomy that males compete for and females choose mates.
Polygyny does not necessarily entail sexualselection of men. All factors that affect the operational sex ratio must be considered. Data from contemporary hunter-gatherers indicate higher mortality rates in men than in women, and lost female reproductive time. If sexualselection did occur in ancestral hunter-gatherers, it was probably men selecting women and not women selecting men.
Our social role/biosocial theory provides a more adequate account of aggression sex differences than does Archer's sexualselection theory. In our theory, these sex differences arise flexibly from sociocultural and ecological forces in interaction with humans' biology, as defined by female and male physical attributes and reproductive activities. Our comments elaborate our theory's explanations for the varied phenomena that Archer presents.
Although "intrasexual selection" has been accepted as the mechanism by which males evolve elaborate secondary sexual traits which are used in aggressive contests, the importance of "intersexual selection" as a mechanism by which males have acquired exaggerated traits to display to females during courtship was less readily accepted. In spite of this scepticism, several genetic models have supported the latter idea, and many empirical studies showed that females were generally more discriminating in mate choice than males, because (...) of differences in relative investment between sexes. Nowadays, this idea is reinforced by various concepts (parental investment, potential reproductive rate, environmental potential for polygamy...) which stress that the strength of sexualselection is related to many interdependent factors, such as mating systems, resource distribution (food, habitat, mate), life history and other ecological characteristics. The case of Salmonids is presented here to show how novel information on sexualselection has contributed to the understanding of the plasticity of breeding patterns in the context of evolutionary biology. (shrink)
This essay traces the interlinked origins of two concepts found in Charles Darwin's writings: "unconscious selection," and sexualselection as applied to humanity's anatomical race distinctions. Unconscious selection constituted a significant elaboration of Darwin's artificial selection analogy. As originally conceived in his theoretical notebooks, that analogy had focused exclusively on what Darwin later would call "methodical selection," the calculated production of desired changes in domestic breeds. By contrast, unconscious selection produced its results unintentionally (...) and at a much slower pace. Inspiration for this concept likely came from Darwin's early reading of works on both animal breeding and physical ethnology. Texts in these fields described the slow and unplanned divergence of anatomical types, whether animal or human, under the guidance of contrasting ideals of physical perfection. These readings, it is argued, also led Darwin to his theory of sexualselection as applied to race, a theme he discussed mainly in his book The Descent of Man. There Darwin described how the racial version of sexualselection operated on the same principle as unconscious selection. He thereby effectively reunited these kindred concepts. (shrink)
Psychological altruism (being motivated by the needs of others) has a tendency to produce behaviour that is costly in evolutionary terms. How, then, could the capacity for psychological altruism evolve? One suggestion is that it is the result of sexualselection. There are, however, two problems that face such an account: first, it is not clear that the resulting behaviour would be altruistic in the relevant sense, and second, it does not seem to fit with key features of (...) our actual helping behaviour. I will argue that both of these problems can be avoided if we adopt a modular account of desire formation. (shrink)
Geoffrey Miller argues that we can account for the evolution of human art and altruism via the action of sexualselection. He identifies five characteristics supposedly unique to sexual adaptations: fitness indicating cost; involvement in courtship; heritability; variability; and sexual differentiation. Miller claims that art and altruism possess these characteristics. I argue that not only does he not demonstrate that art and altruism possess these characteristics, one can also explain the origins of altruism via a form (...) of group selection and traits with the five characteristics in terms of a process I call "cultural sexualselection.". (shrink)
My response is organized into three sections. The first revisits the theme of the target article, the explanatory power of sexualselection versus social role theory. The second considers the range and scope of sexualselection, and its application to human sex differences. Two topics are examined in more detail: (1) the paternity uncertainty theory of partner violence; (2) evolution of inter-group aggression. Section 4 covers ultimate and proximal explanations and their integration within an ethological approach. (...) I consider the development of sex differences in aggression, and their causal mechanisms, within this framework. (shrink)
Del Giudice's model of sex-specific attachment patterns demonstrates the usefulness of infusing life history theory with principles of sexualselection. We believe a full synthesis between the two theories provides a foundation for a comprehensive model of alternative reproductive strategies. We extend Del Giudice's ideas based on our own program of research, focusing specifically on the importance of intrasexual competition and the individual phenotype during development.
Archer provides seemingly compelling evidence for his claim that sexualselection explains sex differences in human aggression better than social role theory. I challenge Archer's interpretation of some of this evidence. I argue that the same evidence could be used to support the claim that what has been selected for is the ability to curb aggression and discuss implications for Archer's theory.
I have provided evidence that Geary's model does not explain male dominance in spatial abilities by sexualselection. The current literature concerning the relations of nonverbal IQ to testosterone, hand preference, and right- and left-hand skill, as well as the organizing effects of testosterone on cerebral lateralization during the perinatal period, does not support Geary's arguments.
I suggest that a communicative context that has the potential to establish and maintain a shared advantage of behavioral lateralization should be identified in the domain of sexualselection, specifically in the interactions that individuals exploit to assess the fitness of potential mates.
In this paper, we argue that mating games, a concept that denotes cultural practices characterized by a competitive element and an ornamental character, are essential drivers behind the emergence and maintenance of human cultural practices. In order to substantiate this claim, we sketch out the essential role of the game’s players and audience, as well as the ways in which games can mature and turn into relatively stable cultural practices. After outlining the life phase of mating games – their emergence, (...) rise, maturation, and possible eventual decline – we go on to argue that participation in these games (in each phase) does make sense from an adaptationist point of view. The strong version of our theory which proposes that all cultural practices are, or once were, mating games, allows us to derive a set of testable predictions for the fields of archaeology, economics, and psychology. (shrink)
Is it possible to be a socio-biologist and a feminist? Socio-biology has been accused of being a macho ideological arsenal, which seems to exclude in advance any possibility of amending it. However that was the project of several female researchers (in particular S. B. Hrdy and P. A. Gowaty), who suggested adopting the science’s theoretical framework in order to change it from within. This has been expressed in a change of focus: an appeal to take account of female strategies and (...) their evolution as well as the "sex war" at work in process of reproduction. This opening out of socio-biology’s theoretical framework has not been undertaken in the name of the privilege of a "female perspective" but it has without a doubt been nourished by the researchers’ marginal position in their discipline as well as their political involvement. "Male" contributions, such as W. G. Eberhard’s work on the "female’s cryptic choice", are also part of this movement though they do not claim allegiance to it. Similarly, a critical study has been carried out on the vocabulary of socio-biology: not in order to exercise a "politically correct" ideological tyranny but to improve the efficiency of the conceptual tools introduced by the science. Today some feminists think feminism should incorporate socio-biology’s results but resistance still remains strong. Though many feminists think feminism has more to bring to biology than the reverse, many biologists consider that feminism is just an ideology that should remain apart from scientific work. (shrink)
Nothing is gained by opposing and or by proclaiming the supremacy of one over the other. Instead, we should develop a unitary model of gene-culture coevolution, allowing for the complex interaction of both, and varying importance of each, all within our double, species-specific, adaptive, evolutionary track.