Niedenthal et al's classification of smiles erroneously conflates psychological mechanisms and adaptive functions. This confusion weakens the rationale behind the types of smiles they chose to individuate, and it obfuscates the distinction between the communicative versus denotative nature of smiles and the role of perceived-gaze direction in emotion recognition.

There are three concerns regarding Rachlin's altruism model. First, proximal causal mechanisms such as those identified by cognitive neuroscientists and behavioral neuropharmacologists are not emphasized. Second, there is a lack of clear testable hypotheses. And third, extreme forms of altruism are emphasized rather than common forms. We focus on an overarching theme – proximal mechanisms of individual differences in altruism.

To understand the consequences of cleansing, Lee and Schwarz favor a grounded procedures perspective over recently developed disgust theory. We believe that this position stems from three errors: (1) interpreting cleansing effects as broader than they are; (2) not detailing the proximate mechanisms underlying disgust; and (3) not detailing adaptive function versus system byproducts when developing the grounded procedures perspective.

There is little fear that the concept of motivational bias as proposed by Mele is likely to dampen the current academic ferment (see Mele's Introduction) with respect to self-deception for several reasons: (a) like philosophy, science has more recently abandoned the heuristic of a rational human mind; (b) the concept is parsimonious, applicable to many research topics other than self-deception, and, therefore, scientifically serviceable; (c) as a proximal mechanism it addresses process rather than function, that is, how rather than why (...) questions; (d) it is not as interesting a question as why there is a high prevalence of “real” self-deception (i.e., “garden-variety self-deception” as described by Mele, see sect. 6); and (e) a more penetrating issue is whether “real” self-deception is adaptive. (shrink)

We received several commentaries both challenging and supporting our hypothesis. We thank the commentators for their thoughtful contributions, bringing together alternative hypotheses, complementary explanations, and appropriate corrections to our model. Here, we explain further our hypothesis, using more explicitly the framework of evolutionary social sciences. We first explain what we believe is the ultimate function of fiction in general (i.e., entertainment) and how this hypothesis differs from other evolutionary hypotheses put forward by several commentators. We then turn to the (...) class='Hi'>proximate features that make imaginary worlds entertaining and, therefore, culturally successful. We finally explore how these insights may explain the distribution of imaginary worlds across time, space, age, and social classes. (shrink)

The study of reciprocal altruism, or the exchange of goods and services between individuals, requires attention to both evolutionary explanations and proximate mechanisms. Evolutionary explanations have been debated at length, but far less is known about the proximate mechanisms of reciprocity. Our own research has focused on the immediate causes and contingencies underlying services such as food sharing, grooming, and cooperation in brown capuchin monkeys and chimpanzees. Employing both observational and experimental techniques, we have come to (...) distinguish three types of reciprocity. Symmetry-based reciprocity is cognitively the least complex form, based on symmetries inherent in dyadic relationships (e.g., mutual association, kinship). Attitudinal reciprocity, which is more cognitively complex, is based on the mirroring of social attitudes between partners and is exhibited by both capuchin monkeys and chimpanzees. Finally, calculated reciprocity, the most cognitively advanced form, is based on mental scorekeeping and is found only in humans and possibly chimpanzees. (shrink)

De Dreu and Gross's description of the proximate mechanisms conditioning success in intergroup conflict omits humans' deontological morality. Drawing on research on sacralization and moral objectivism, I show how “moral rigidity” may have evolved through partner selection mechanisms to foster coalitions’ cohesion and combativeness in intergroup conflict.

While admirable, Guala's discussion of reciprocity suffers from a confusion between proximate causes (psychological mechanisms triggering behaviour) and ultimate causes (evolved function of those psychological mechanisms). Because much work on commits this error, I clarify the difference between proximate and ultimate causes of cooperation and punishment. I also caution against hasty rejections of of experimental evidence.

What role does non-genetic inheritance play in evolution? In recent work we have independently and collectively argued that the existence and scope of non-genetic inheritance systems, including epigenetic inheritance, niche construction/ecological inheritance, and cultural inheritance—alongside certain other theory revisions—necessitates an extension to the neo-Darwinian Modern Synthesis (MS) in the form of an Extended Evolutionary Synthesis (EES). However, this argument has been challenged on the grounds that non-genetic inheritance systems are exclusively proximate mechanisms that serve the ultimate function of (...) calibrating organisms to stochastic environments. In this paper we defend our claims, pointing out that critics of the EES (1) conflate non-genetic inheritance with early 20th-century notions of soft inheritance; (2) misunderstand the nature of the EES in relation to the MS; (3) confuse individual phenotypic plasticity with trans-generational non-genetic inheritance; (4) fail to address the extensive theoretical and empirical literature which shows that non-genetic inheritance can generate novel targets for selection, create new genetic equilibria that would not exist in the absence of non-genetic inheritance, and generate phenotypic variation that is independent of genetic variation; (5) artificially limit ultimate explanations for traits to gene-based selection, which is unsatisfactory for phenotypic traits that originate and spread via non-genetic inheritance systems; and (6) fail to provide an explanation for biological organization. We conclude by noting ways in which we feel that an overly gene-centric theory of evolution is hindering progress in biology and other sciences. (shrink)

Ernst Mayr proposed a distinction between “proximate”, mechanistic, and “ultimate”, evolutionary, causes of biological phenomena. This dichotomy has influenced the thinking of many biologists, but it is increasingly perceived as impeding modern studies of evolutionary processes, including study of “niche construction” in which organisms alter their environments in ways supportive of their evolutionary success. Some still find value for this dichotomy in its separation of answers to “how?” versus “why?”questions about evolution. But “why is A?” questions about evolution necessarily (...) take the form “how does A occur?”, so this separation is illusory. Moreover, the dichotomy distorts our view of evolutionary causality, in that, contra Mayr, the action of natural selection, driven by genotype-phenotype-environment interactions which constitute adaptations, is no less “proximate” than the biological mechanisms which are altered by naturally selected genetic variants. Mayr’s dichotomy thus needs replacement by more realistic, mechanistic views of evolution. From a mechanistic viewpoint, there is a continuum of adaptations from those evolving as responses to unchanging environmental pressures to those evolving as the capacity for niche construction, and intermediate stages of this can be identified. Some biologists postulate an association of “phenotypic plasticity” (phenotype-environment covariation with genotype held constant) with capacity for niche construction. Both “plasticity” and niche construction comprise wide ranges of adaptive mechanisms, often fully heritable and resulting from case-specific evolution. Association of “plasticity” with niche construction is most likely to arise in systems wherein capacity for complex learning and behavioral flexibility have already evolved. (shrink)

Ernst Mayr’s classical work on the nature of causation in biology has had a huge influence on biologists as well as philosophers. Although his distinction between proximate and ultimate causation recently came under criticism from those who emphasize the role of development in evolutionary processes, the formal relationship between these two notions remains elusive. Using causal graph theory, this paper offers a unified framework to systematically translate a given “proximate” causal structure into an “ultimate” evolutionary response, and illustrates (...) evolutionary implications of various kinds of causal mechanisms including epigenetic inheritance, maternal effects, and niche construction. These results not only reveal the essential interplay between proximate and ultimate causation in the study of evolution, but also provide a formal method to evaluate or discover non-standard or yet unknown evolutionary phenomena. (shrink)

The majority of the commentaries focused on excessive crying and colic and included two major themes: the consideration of proximate physiological mechanisms, and challenges to my interpretation of the signal functions of early infant crying amount. I initially concluded that none of the competing signaling hypotheses enjoyed strong support, but I nevertheless favored the signaling vigor hypothesis above the signaling need and manipulation hypotheses. Consideration of the neurobiological causation of the n-shaped crying curve and further evidence and argumentation (...) concerning the potential signal functions, however, do not allow for the elevation of any one of these hypotheses above the others, and it remains the case that none are strongly supported. Taken together, however, the target article and commentary do provide a solid foundation for further research. In the target article, I also proposed a model of how infant cry acoustics can influence patterns of care and abuse. Commentary has enriched this model by including the consideration of developmental changes in cry acoustics across early infancy, and by further integrating the cry signal with other modalities of communication and with later development. I trust that the foregoing will show that the joint pursuit of the proximate mechanisms and the potential signal functions of early infant cry amount and cry acoustics should prove fruitful. Before embarking on my reevaluation, however, I begin this response by addressing the issue of consciousness in evolutionary accounts of signaling. (shrink)

Romantic love is a phenomenon of immense interest to the general public as well as to scholars in several disciplines. It is known to be present in almost all human societies and has been studied from a number of perspectives. In this integrative review, we bring together what is known about romantic love using Tinbergen’s “four questions” framework originating from evolutionary biology. Under the first question, related to mechanisms, we show that it is caused by social, psychological mate choice, (...) genetic, neural, and endocrine mechanisms. The mechanisms regulating psychopathology, cognitive biases, and animal models provide further insights into the mechanisms that regulate romantic love. Under the second question, related to development, we show that romantic love exists across the human lifespan in both sexes. We summarize what is known about its development and the internal and external factors that influence it. We consider cross-cultural perspectives and raise the issue of evolutionary mismatch. Under the third question, related to function, we discuss the fitness-relevant benefits and costs of romantic love with reference to mate choice, courtship, sex, and pair-bonding. We outline three possible selective pressures and contend that romantic love is a suite of adaptions and by-products. Under the fourth question, related to phylogeny, we summarize theories of romantic love’s evolutionary history and show that romantic love probably evolved in concert with pair-bonds in our recent ancestors. We describe the mammalian antecedents to romantic love and the contribution of genes and culture to the expression of modern romantic love. We advance four potential scenarios for the evolution of romantic love. We conclude by summarizing what Tinbergen’s four questions tell us, highlighting outstanding questions as avenues of potential future research, and suggesting a novel ethologically informed working definition to accommodate the multi-faceted understanding of romantic love advanced in this review. (shrink)

The explanatory value of niche construction can be strengthened by firm footing in semiotic theory. Anthropologists have a unique perspective on the integration of such diverse approaches to human action and evolutionary processes. Here, we seek to open a dialogue between anthropology and biosemiotics. The overarching aim of this paper is to demonstrate that niche construction, including the underlying mechanism of reciprocal causation, is a semiotic process relating to biological development as well as cognitive development and cultural change. In making (...) this argument we emphasize the semiotic mechanisms underlying the niche concept. We argue that the “niche” in ecology and evolutionary biology can be consistent with the Umwelt of Jakob von Uexkull. Following John Deely we therefore suggest that investigations into the organism—environment interface constituting niche construction should emphasize the semiotic basis of experience. Peircean signs are pervasive and allow for flexible interpretations of phenomena in relation to the perceptual and cognitive capacities of the behaving organism, which is particularly pertinent for understanding the relation of proximate/ultimate selective forces as co-productive. Additionally, theoretical work by Kinji Imanishi on the evolution of daily life and Gregory Bateson’s relational view of evolution both support the linkage between proximate and ultimate evolutionary processes of causation necessitated by the niche construction perspective. We will then apply this theoretical framework to two specific examples: 1) hominin evolution, including uniquely human cultural behaviors with niche constructive implications; and 2) the multispecies and anthropocentric niche of human-dog coevolution from which complex cognitive capacities and semiotic relationships emerged. The intended outcome of this paper is the establishment of concrete semiotic mechanisms and theory underlying niche constructive behavior which can then be applied to a broad spectrum of organisms to contextualize the reciprocal relation between proximate and ultimate drivers of behavior. (shrink)

The question “what is an interpretation?” is often intertwined with the perhaps even harder question “what is a scientific theory?”. Given this proximity, we try to clarify the first question to acquire some ground for the latter. The quarrel between the syntactic and semantic conceptions of scientific theories occupied a large part of the scenario of the philosophy of science in the 20th century. For many authors, one of the two currents needed to be victorious. We endorse that such debate, (...) at least in the terms commonly expressed, can be misleading. We argue that the traditional notion of “interpretation” within the syntax/semantic debate is not the same as that of the debate concerning the interpretation of quantum mechanics. As much as the term is the same, the term “interpretation” as employed in quantum mechanics has its meaning beyond (pure) logic. Our main focus here lies on the formal aspects of the solutions to the measurement problem. There are many versions of quantum theory, many of them incompatible with each other. In order to encompass a wider variety of approaches to quantum theory, we propose a different one with an emphasis on pure formalism. This perspective has the intent of elucidating the role of each so-called “interpretation” of quantum mechanics, as well as the precise origin of the need to interpret it. (shrink)

Music's efficacy as a credible signal and/or as a tool for social bonding piggybacks on a diverse set of biological and cognitive processes, implying different proximate mechanisms. It is likely this multiplicity of mechanisms that explains why it is so difficult to account for music's putative biological role, as well as its possible origins, by proposing a single adaptive function.

Causal mechanisms' portability and their predictions in sometimes counterfactual settings point to the value of studies with details of interactions and/or convenience samples that depart from those in the proximate contexts of the phenomena of interest. The proper role of such contexts must be construed within an explanatory framework attentive to the nature and properties of relevant causal mechanisms.

L’une des dernières œuvres de Mike Kelley, qui comprend plusieurs séries réalisées entre 1999 et 2011, est consacrée à Kandor, la ville natale de Superman sur la planète Krypton : une architecture phallique miniaturisée, maintenue sous cloche dans une atmosphère séparée, et dont la forme, dans les vignettes des comics d’origine, ne cesse de subir des variations au fil des épisodes. Partant de ces dessins à la mémoire labile, Kelley produit un ensemble d’installations multimédias qui reprennent des codes visuels typiques (...) de la science-fiction, mais dont l’expérience, pour le spectateur, s’avère excluante plutôt qu’immersive. D’un point de vue phénoménologique, il est question d’appréhender les Kandors comme des réticences, et d’interroger les différents enjeux de cette présence paradoxale. Porteuses de fonctions complexes à la portée psychique autant que collective, ces installations sont d’abord des paraboles du conditionnement social et de ses moules, ce qui inclut et met à l’épreuve leurs propres modalités de réception critique. Par ailleurs, les Kandors engagent tout un jeu de réminiscences formelles qui questionne les mécanismes de fabrication de la mémoire officielle, et la relation amnésique que celle-ci entretient avec certains types de formes principalement issues de la culture populaire. One of Mike Kelley’s latest works, which includes several series produced between 1999 and 2011, is dedicated to Kandor, Superman’s hometown on the planet Krypton: a miniature phallic architecture, kept in a bell jar in a separate atmosphere, and the form of which, portrayed in the original comic strips, continues to undergo change through each episode. Based on these labile memory drawings, Kelley produces a set of multimedia installations which draw from Sci-Fi visual codes, but the experience of which, for the viewer, is exclusive rather than immersive. From a phenomenological point of view, we must consider the Kandors as reluctances, and question the different stakes of this paradoxical presence. Carrying complex functions with psychic as well as collective scope, they will first be seen as parables of social conditioning, including their own critical reception. Moreover, the Kandors imply a whole game of formal recollections which questions the mechanisms of manufacturing official memory, and the amnesic relationship which this maintains with certain types of forms derived mainly from popular culture. (shrink)

In most social species, position in the male social hierarchy and reproductive success are positively correlated; in humans, however, this relationship is less clear, with studies of traditional societies yielding mixed results. In the most economically advanced human populations, the adaptiveness of status vanishes altogether; social status and fertility are uncorrelated. These findings have been interpreted to suggest that evolutionary principles may not be appropriate for the explanation of human behavior, especially in modern environments. The present study tests the adaptiveness (...) of social status with actual mating and reproductive data in a representative sample of males from an industrial society. Reproductive success, even when assessed by a more reliable measure ofactualmale fertility than the one commonly used, fails to correlate with social status. In striking contrast, however, status is found to be highly correlated withpotentialfertility, as estimated from copulation frequency. Status thus accounts for as much as 62% of the variance in thisproximatecomponent of fitness. This pattern is remarkably similar to what is found in many traditional societies and would result in a substantial positive relationship between cultural and reproductive success in industrial populations were it not for the novel conditions imposed by contraception and monogamy. Various underlying mechanisms are suggested for these findings, illustrating the value of current behavioral and reproductive data in the study of adaptation. It is concluded that evolutionary explanations of human behavior remain entirely relevant in modern societies. (shrink)

The act of killing self contradicts the central purpose of human evolution, that is, survival and propagation of one’s genetic material. Yet, it continues to be one of the leading causes of human death. A handful of theories in the realm of evolutionary psychology have attempted to explain human suicide. The current article analyses the major components of certain prominent viewpoints, namely, Inclusive fitness, Bargaining model, Pain-Brain model, Psychological aposematism, and few other perspectives. The article argues that relatively more weightage (...) has been given to understanding ultimate (the “why”) rather than proximate (the “how”) functionality of suicidal acts. Evolutionary theorists have consistently pointed out that to comprehensively understand a trait or behavior, one needs to delineate not only how it supports survival but also the evolution of the mechanisms underlying the trait or behavior. Existing theories on suicide have primarily focused on its fitness benefits on surviving kin instead of providing evolutionary explanations of the more complex mechanisms leading up to such self-destructive motivations. Thus, the current paper attempts to highlight this gap in theorizing while suggesting probable proximate explanations of suicide which stresses the need to diffuse attention paid to fitness consequences of the act alone. We speculate that such explorations are needed in order to build a robust and comprehensive evolutionary theory of human suicide. (shrink)

Recent studies support a model in which the progeny of SOX9+ epithelial progenitors at the distal tip of lung branches undergo cell allocation and differentiation sequentially along the distal‐to‐proximal axis. Concomitant with the elongation and ramification of lung branches, the descendants of the distal SOX9+ progenitors are distributed proximally, express SOX2, and differentiate into cell types in the conducting airways. Amid subsequent sacculation, the distal SOX9+ progenitors generate alveolar epithelial cells to form alveoli. Sequential cell allocation and differentiation are integrated (...) with the branching process to generate a functional branching organ. This review focuses on the roles of SOX9+ cells as precursors for new branches, as the source of various cell types in the conducting airways, and as progenitors of the alveolar epithelium. All of these processes are controlled by multiple signaling pathways. Many mouse mutants with defective lung branching contain underlying defects in one or more steps of cell allocation and differentiation of SOX9+ progenitors. This model provides a framework to understand the molecular basis of lung phenotypes and to elucidate the molecular mechanisms of lung patterning. It builds a foundation on which comparing and contrasting the mechanisms employed by different branching organs in diverse species can be made. (shrink)

Philosophers of science and medicine now aspire to provide useful, socially relevant accounts of mechanism. Existing accounts have forged the path by attending to mechanisms in historical context, scientific practice, the special sciences, and policy. Yet, their primary focus has been on more proximate issues related to therapeutic effectiveness. To take the next step toward social relevance, we must investigate the challenges facing researchers, clinicians, and policy makers involving values and social context. Accordingly, we learn valuable lessons about (...) the connections between mechanistic processes and more fundamental reasons for medical interventions, particularly moral, ethical, religious, and political concerns about health, agency, and power. This paper uses debates over the controversial morning-after pill to gain insight into the deeper reasons for the production and use of mechanistic knowledge throughout biomedical research, clinical practice, and governmental regulation. To practice socially relevant philosophy of science, I argue that we need to account for mechanistic knowledge beyond immediate effectiveness, such as how it can also provide moral guidance, aid ethical categorization in the clinic, and function as a political instrument. Such insights have implications for medical epistemology, including the value-laden dimensions of mechanistic reasoning and the “epistemic friction” of values. Furthermore, there are broader impacts for teaching research ethics and understanding the role of science advisors as political advocates. (shrink)

Cooperation is common across nonhuman animal taxa, from the hunting of large game in lions to the harvesting of building materials in ants. Theorists have proposed a number of models to explain the evolution of cooperative behavior. These ultimate explanations, however, rarely consider the proximate constraints on the implementation of cooperative behavior. Here we review several types of cooperation and propose a suite of cognitive abilities required for each type to evolve. We propose that several types of cooperation, though (...) theoretically possible and functionally adaptive, have not evolved in some animal species because of cognitive constraints. We argue, therefore, that future modeling efforts and experimental investigations into the adaptive function of cooperation in animals must be grounded in a realistic assessment of the psychological ingredients required for cooperation. Such an approach can account for the puzzling distribution of cooperative behaviors across taxa, especially the seemingly unique occurrence of cooperation observed in our own species. (shrink)

In this journal, Schulte develops a novel solution to the problem of distal content: by virtue of what is a mental representation about a distal object rather than a more proximal cause of that representation? Schulte maintains that in order for a representation to have a distal content, it must be produced by a constancy mechanism, along with two other conditions. I raise three objections to his solution. First, a core component of Schulte's solution is just a restrictive version of (...) Dretske's solution, but Schulte gives no argument for his restriction. Second, his proposed solution to a disjunction problem is ad hoc. Finally, his ‘far-out’ version of the distality problem is not a version of the distality problem at all. I conclude that Dretske's solution is preferable to Schulte's. (shrink)

While much interdisciplinarity brings together proximate fields, broad interdisciplinarity sees integration between disciplines that are perceived to be non-neighboring. This paper argues that the heterogeneity among disciplines in broad interdisciplinarity calls for stricter epistemic norms of testimony for experts that act as translators between the disciplines than those suggested for intra-scientific testimony. The paper is structured around two case studies: the affective turn in social theorizing and the use of quantum mechanics in critical theory as exemplified by Vicky Kirby’s (...) use of work by Karen Barad. These are argued to be instances of broad interdisciplinary borrowing where few translators have joint expertise in both disciplines. For most, therefore, the engagement with for instance the integration between quantum mechanics and critical theory is possible only by the aid of translators. For those without sufficient interactional expertise, however, the epistemic credentials of the translations they inevitably rely upon are inscrutable. Furthermore, any comparison between translations is challenged since translations are argued to be few due to the cognitive divergence between disciplines in broad interdisciplinarity. Consequently, the epistemic integrity of broad interdisciplinarity can only be secured through additional norms of testimony for translators. The paper proposes that (a) all translator’s testimony in broad interdisciplinarity must aim to be neutral with respect to disputed issues within the relevant disciplines and (b) any deviation from (a) must be clearly highlighted. (shrink)

Anorexia nervosa remains an enigma among Western cultures. Various causal explanations have been offered, encompassing biological, psychological, and sociocultural models. These explanations, however, focus on the immediate or proximal mechanisms of causation. A more thorough understanding of anorexia nervosa can be achieved by understanding the relationship between these factors and ultimate causation, the level of explanation which deals with individual reproductive fitness. This paper reviews the biological, psychological, sociocultural, and evolutionary models and indicates a necessary synthesis between proximate (...) and ultimate levels of causation in examining the anorexia nervosa puzzle. (shrink)

8 March, now known as International Women’s Day, is a day for feminist claims where demonstrations are organized in over 150 countries, with the participation of millions of women all around the world. These demonstrations can be viewed as collective rituals and thus focus attention on the processes that facilitate different psychosocial effects. This work aims to explore the mechanisms involved in participation in the demonstrations of 8 March 2020, collective and ritualized feminist actions, and their correlates associated with (...) personal well-being and collective well-being, collective efficacy and collective growth, and behavioral intention to support the fight for women’s rights. To this end, a cross-cultural study was conducted with the participation of 2,854 people from countries in Latin America and Europe, with a retrospective correlational cross-sectional design and a convenience sample. Participants were divided between demonstration participants and non-demonstrators or followers who monitored participants through the media and social networks. Compared with non-demonstrators and with males, female and non-binary gender respondents had greater scores in mechanisms and criterion variables. Further random-effects model meta-analyses revealed that the perceived emotional synchrony was consistently associated with more proximal mechanisms, as well as with criterion variables. Finally, sequential moderation analyses showed that proposed mechanisms successfully mediated the effects of participation on every criterion variable. These results indicate that participation in 8M marches and demonstrations can be analyzed through the literature on collective rituals. As such, collective participation implies positive outcomes both individually and collectively, which are further reinforced through key psychological mechanisms, in line with a Durkheimian approach to collective rituals. (shrink)

Evolutionary psychology is a science in the making, working toward the goal of showing how psychological adaptation underlies much human behavior. The knee-jerk reaction that sociobiology is unscientific because it tells “just-so stories” has become a common charge against evolutionary psychology as well. My main positive thesis is that inference to the best explanation is a proper method for evolutionary analyses, and it supplies a new perspective on the issues raised in Schlinger's (1996) just-so story critique. My main negative thesis (...) is that, like many nonevolutionist critics, Schlinger's objections arise from misunderstandings of the evolutionary approach.Evolutionary psychology has progressed beyond telling just-so stories. It has found a host of ingenious special techniques to test hypotheses about the adaptive significance and proximate mechanisms of behavior. Naturalistic data using the comparative method combined with controlled tests using statistical analyses of data provide good evidence for a variety of hypotheses about behavioral control mechanisms — whether in nonhumans or in humans. For instance, the work of Gangestad and Thornhill on evolved mate preferences and fluctuating asymmetry of body type (FA) is a model of success. As the quantity and quality of evidence increase, we are entitled not just to regard such evolutionary hypotheses as preferable, but also as true. Such studies combine to show that the best explanation of “the psychic unity of humankind” — common patterns across societies, history, and cultures exposed by evolutionists — is the gendered, adapted, evolved species-typical design of the mind. (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)

This collection reports on the latest research on an increasingly pivotal issue for evolutionary biology: cooperation. The chapters are written from a variety of disciplinary perspectives and utilize research tools that range from empirical survey to conceptual modeling, reflecting the rich diversity of work in the field. They explore a wide taxonomic range, concentrating on bacteria, social insects, and, especially, humans. -/- Part I (“Agents and Environments”) investigates the connections of social cooperation in social organizations to the conditions that make (...) cooperation profitable and stable, focusing on the interactions of agent, population, and environment. Part II (“Agents and Mechanisms”) focuses on how proximate mechanisms emerge and operate in the evolutionary process and how they shape evolutionary trajectories. Throughout the book, certain themes emerge that demonstrate the ubiquity of questions regarding cooperation in evolutionary biology: the generation and division of the profits of cooperation; transitions in individuality; levels of selection, from gene to organism; and the “human cooperation explosion” that makes our own social behavior particularly puzzling from an evolutionary perspective. (shrink)

Juslin & Vll (J&V) advance our understanding of the proximate mechanisms underlying emotional responses to music, but fail to integrate their findings into a comprehensive evolutionary model that addresses the adaptive functions of these responses. Here we offer such a model by examining the ontogenetic relationship between music, ritual, and symbolic abstraction and their role in facilitating social coordination and cooperation.

Paternity certainty and matrilineal family ties have been used to explain the asymmetric caregiving of grandparents and aunts and uncles. The proximate mechanisms underlying biased kin investment, however, remain unclear. A central question of the study presented here was whether the parent-kin relationship is an important link in the caregiving. In a two-generational questionnaire study, we asked subjects to estimate the intensity of their relationships to parents, grandparents, aunts, and uncles (emotional closeness, investment received in childhood). In addition, (...) the subjects’ parents rated their emotional closeness to their parents and siblings. We found that the parent-kin relationship was closely linked to the relatives’ child care and could partly explain asymmetric caregiving. Maternal aunts played a special role as caregivers. Especially the mother’s younger or last-born sister cared intensively for nieces and nephews, regardless of her closeness to the subjects’ mother. (shrink)

I examine the relationship between evolutionary definitions of altruism that are based on fitness effects and psychological definitions that are based on the motives of the actor. I show that evolutionary altruism can be motivated by proximate mechanisms that are psychologically either altruistic or selfish. I also show that evolutionary definitions do rely upon motives as a metaphor in which the outcome of natural selection is compared to the decisions of a psychologically selfish (or altruistic) individual. Ignoring the (...) precise nature of both psychological and evolutionary definitions has obscured many important issues, including the biological roots of psychological altruism. (shrink)

Eating disorders are evolutionarily novel conditions that lead to some of the highest mortality rates of all psychiatric disorders. Several evolutionary hypotheses have been proposed for eating disorders, but only the intrasexual competition hypothesis is extensively supported by evidence. We present the mismatch hypothesis as a necessary extension to the current theoretical framework of eating disorders. This hypothesis explains the evolutionarily novel adaptive metaproblem that has arisen when mating motives and readily available food rewards conflict with one another. This situation (...) is exacerbated in contemporary environments characterized by sedentary lifestyles, caloric surplus and the ubiquity of social comparisons that take place via social media. Our psychoneuroimmunological model connects ultimate-level causation with proximate mechanisms by showing how the adaptive metaproblem between mating motives and food rewards leads to chronic stress and, further, to disordered eating. Chronic stress causes neuroinflammation, which increases susceptibility to OCD-like behaviors that typically co-occur with eating disorders. Chronic stress upregulates the serotonergic system and causes dysphoric mood in patients with restricting-type anorexia nervosa. Dieting, however, reduces serotonin levels and dysphoric mood, leading to a vicious serotonergic-homeostatic stress/starvation cycle whereby cortisol and neuroinflammation increase through stringent dieting. Between-individual and within-individual variation in eating disorders partially arises from (co)variation in gut microbiota and stress responsivity, which influence neuroinflammation and the serotonergic system. In binge-related eating disorders, even a short period of fasting drops serotonin levels, a state alleviated by binge eating. Eating disorder treatments should aim to reduce the chronic stress, neuroinflammation, stress responsivity and gut dysbiosis that fuel the disorders. We review the advances that have been made in recent years in understanding how to best treat eating disorders, outlining directions for future clinical research. Connecting ultimate causes with proximate mechanisms and treating biopsychosocial causes rather than manifest symptoms will enable more effective and sophisticated long-term interventions for the millions of people who suffer from eating disorders. (shrink)

Within evolutionary biology, life-history theory is used to explain cross-species differences in allocation strategies regarding reproduction, maturation, and survival. Behavioral scientists have recently begun to conceptualize such strategies as a within-species individual characteristic that is predictive of behavior. Although life history theory provides an important framework for behavioral scientists, the psychometric approach to life-history strategy measurement—as operationalized by K-factors—involves conceptual entanglements. We argue that current psychometric approaches attempting to identify K-factors are based on an unwarranted conflation of functional descriptions and (...) proximate mechanisms—a conceptual mix-up that may generate unviable hypotheses and invites misinterpretation of empirical findings. The assumptions underlying generic psychometric methodology do not allow measurement of functionally defined variables; rather these methods are confined to Mayr’s proximate causal realm. We therefore conclude that K-factor scales lack validity, and that life history strategy cannot be identified with psychometrics as usual. To align theory with methodology, suggestions for alternative methods and new avenues are proposed. (shrink)

In our response to the 27 commentaries, we refine the theoretical claims, clarify several misconceptions of our framework, and explore substantial disagreements. In doing so, we show that our framework accommodates multiple historical scenarios; debate the historical evidence, particularly about “pre-Axial” religions; offer important details about cultural evolutionary theory; clarify the termprosociality;and discuss proximal mechanisms. We review many interesting extensions, amplifications, and qualifications of our approach made by the commentators.

Our objective is to test an optimality model of human fertility that specifies the behavioral requirements for fitness maximization in order (a) to determine whether current behavior does maximize fitness and, if not, (b) to use the specific nature of the behavioral deviations from fitness maximization towards the development of models of evolved proximate mechanisms that may have maximized fitness in the past but lead to deviations under present conditions. To test the model we use data from a (...) representative sample of 7,107 men living in Albuquerque, New Mexico, between 1990 and 1993. The model we test proposes that low fertility in modern settings maximizes number of grandchildren as a result of a trade-off between parental fertility and next generation fertility. Results do not show the optimization, although the data do reveal a trade-off between parental fertility and offspring education and income.We propose that two characteristics of modern economies have led to a period of sustained fertility reduction and to a corresponding lack of association between income and fertility. The first is the direct link between costs of investment and wage rates due to the forces of supply and demand for labor in competitive economies. The second is the increasing emphasis on cumulative knowledge, skills, and technologies in the production of resources. Together they produce historically novel conditions. These two features of modern economies may interact with evolved psychological and physiological mechanisms governing fertility and parental investment to produce behavior that maximizes the economic productivity of lineages at the expense of fitness. If cognitive processes evolved to track diminishing returns to parental investment and if physiological processes evolved to regulate fertility in response to nutritional state and patterns of breast feeding, we might expect non-adaptive responses when returns from parental investment do not diminish until extremely high levels are reached. With high economic payoffs from parental investment, people have begun to exercise cognitive regulation of fertility through contraception and family planning practices. Those cognitive processes maynot have evolved to handle fitness trade-offs between fertility and parental investment. (shrink)

I attempt to complement my earlier critiques of human sociobiology, by offering an account of how evolutionary ideas might legitimately be employed in the study of human social behavior. The main emphasis of the paper is the need to integrate studies of proximate mechanisms and their ontogenesis with functional/evolutionary research. Human psychological complexity makes it impossible to focus simply on specific types of human behavior and ask for their functional significance. For any of the kinds of behavior patterns (...) that have occupied human sociobiologists, the underlying proximate mechanisms are very likely to be linked to a broad spectrum of types of behavior, and we cannot expect that natural selection will have acted directly on any individual element from this spectrum. I illustrate this general point with a specific example, considering the traditional sociobiological account of human incest-avoidance and outlining an alternative approach to the phenomena. The example is intended to show the possibility of a more rigorous and sophisticated successor to human sociobiology, which I call "human behavioral ecology". (shrink)

In lieu of an abstract, here is a brief excerpt of the content:The Human Revolution and the Adaptive Function of LiteratureJoseph CarrollIBefore the advent of purely culturalist ways of thinking in the early decades of the twentieth century, the idea of "human nature" was deeply ingrained in the literature and the humanistic social theory of the West.1 In the past three decades, ethology, sociobiology, and evolutionary psychology have succeeded in making the idea of "human nature" once again a commonplace of (...) public discourse, but the actual shape and content of human nature, even among Darwinian social scientists, remains controversial. Human nature is the product of evolution, and for Darwinians, concepts about the structure of human nature are necessarily bound up with concepts about the course of human evolution. My purpose in this essay will be to examine two chief alternatives in the current Darwinian understanding of human evolution and human nature, to advocate one of these alternatives, and to assess its implications for Darwinian literary study. One alternative can be identified with evolutionary psychology, and the other, the one I shall advocate, with evolutionary anthropology and cognitive archaeology. For the sake of economy, I shall refer to the former as the EP model and to the latter as the EACA model.In the late 1980s and early 1990s, the main theoretical controversy in Darwinian social science was that between the sociobiologists and Darwinian anthropologists, on the one side, and the evolutionary psychologists on the other. The point at issue was whether "fitness maximization" or the desire to maximize reproductive success could serve as a direct motive in human behavior. The sociobiologists tended to assume it could; the [End Page 33] evolutionary psychologists instead insisted that fitness maximization was mediated through "proximal mechanisms" such as the male desire for sex and the female desire to acquire resources from male sexual partners. In the arena of received professional opinion, the evolutionary psychologists won this debate, and evolutionary psychology is now the mainstream, establishment creed in Darwinian social science.2 Its hegemony is evidenced by a flood of popular expositions and textbooks. The majority of these expositions give little evidence that the authors are themselves alert to the speculative character of the fundamental concepts of their creed, and the chief tenets of the creed have often been reiterated in a naively uncritical way.The chief tenets of orthodox evolutionary psychology are (a) that the structure of the human mind stabilized during the Pleistocene (beginning about 1.6 million years ago); (b) that the human mind is "modular" in character—consisting of discrete bits of dedicated neural circuitry automatically activated by environmental releasers; (c) that human cognitive aptitudes and motivational structures are firmly adapted to the hunter-gatherer life-style of the Pleistocene—the "environment of evolutionary adaptedness" or EEA; and (d) that the adaptation to Pleistocene conditions carries with it, as a necessary corollary, a "mismatch" between the adapted human mind and all cultural ecologies more complex than that of hunter-gatherers. The core concept, the idea on which all the others depend, is that of the EEA:What we think of as all of human history—from, say, the rise of the Shang, Minoan, Egyptian, Indian, and Sumerian civilizations—and everything we take for granted as normal parts of life—agriculture, pastoralism, governments, police, sanitation, medical care, education, armies, transportation, and so on—are all the novel products of the last few thousand years. In contrast to this, our ancestors spent the last two million years as Pleistocene hunter-gatherers, and, of course, several hundred million years before that as one kind of forager or another. These relative spans are important because they establish which set of environments and conditions defined the adaptive problems the mind was shaped to cope with: Pleistocene conditions, rather than modern conditions.3For evolutionary psychologists, the difference between our Paleolithic ancestors and ourselves is a difference not in anatomical and neurological character but only in external "circumstances." In the EP model, the structure of the human mind at the present time and the structure [End Page 34] of the mind of, say, half a million years ago, would be the same. They would be equally the mind of the Pleistocene.The EP model of... (shrink)

In men and women sexual arousal culminates in orgasm, with female orgasm solely from sexual intercourse often regarded as a unique feature of human sexuality. However, orgasm from sexual intercourse occurs more reliably in men than in women, likely reflecting the different types of physical stimulation men and women require for orgasm. In men, orgasms are under strong selective pressure as orgasms are coupled with ejaculation and thus contribute to male reproductive success. By contrast, women's orgasms in intercourse are highly (...) variable and are under little selective pressure as they are not a reproductive necessity. The proximal mechanisms producing variability in women's orgasms are little understood. In 1924 Marie Bonaparte proposed that a shorter distance between a woman's clitoris and her urethral meatus (CUMD) increased her likelihood of experiencing orgasm in intercourse. She based this on her published data that were never statistically analyzed. In 1940 Landis and colleagues published similar data suggesting the same relationship, but these data too were never fully analyzed. We analyzed raw data from these two studies and found that both demonstrate a strong inverse relationship between CUMD and orgasm during intercourse. Unresolved is whether this increased likelihood of orgasm with shorter CUMD reflects increased penile–clitoral contact during sexual intercourse or increased penile stimulation of internal aspects of the clitoris. CUMD likely reflects prenatal androgen exposure, with higher androgen levels producing larger distances. Thus these results suggest that women exposed to lower levels of prenatal androgens are more likely to experience orgasm during sexual intercourse. . (shrink)

Evolutionary psychology is a science in the making, working toward the goal of showing how psychological adaptation underlies much human behavior. The knee-jerk reaction that sociobiology is unscientific because it tells just-so stories has become a common charge against evolutionary psychology as well. My main positive thesis is that inference to the best explanation is a proper method for evolutionary analyses, and it supplies a new perspective on the issues raised in Schlinger's (1996) just-so story critique. My main negative thesis (...) is that, like many nonevolutionist critics, Schlinger's objections arise from misunderstandings of the evolutionary approach.Evolutionary psychology has progressed beyond telling just-so stories. It has found a host of ingenious special techniques to test hypotheses about the adaptive significance and proximate mechanisms of behavior. Naturalistic data using the comparative method combined with controlled tests using statistical analyses of data provide good evidence for a variety of hypotheses about behavioral control mechanisms — whether in nonhumans or in humans. For instance, the work of Gangestad and Thornhill on evolved mate preferences and fluctuating asymmetry of body type (FA) is a model of success. As the quantity and quality of evidence increase, we are entitled not just to regard such evolutionary hypotheses as preferable, but also as true. Such studies combine to show that the best explanation of the psychic unity of humankind — common patterns across societies, history, and cultures exposed by evolutionists — is the gendered, adapted, evolved species-typical design of the mind. (shrink)

The scaling of body parts is central to the evolution of morphology and shape. Most traits scale proportionally with each other and body size such that larger adults are essentially magnified versions of smaller ones. This pattern is so ubiquitous that departures from it – disproportionate scaling between trait and body size – pique interest because it can generate dramatically exaggerated traits. These extreme morphologies are frequently hypothesized to result from sexual selection and their study has a long history, with (...) several hypotheses seeking to explain their evolution. Despite this effort, surprisingly little progress has been made in demonstrating the forms of selection that produce different scaling patterns or in identifying the mechanisms that underlie the expression and evolution of scaling relationships. Here we review recent insights regarding the proximate mechanisms that regulate and integrate trait growth and that offer a new framework for studying the evolution of morphological scaling. (shrink)

A large body of research links testosterone and cortisol to male-male competition. Yet, little work has explored acute steroid hormone responses to coalitional, physical competition during middle childhood. Here, we investigate testosterone, dehydroepiandrosterone, androstenedione, and cortisol release among ethnically Chinese boys in Hong Kong, aged 8–11 years, during a soccer match and an intrasquad soccer scrimmage, with 63 participants competing in both treatments. The soccer match and intrasquad soccer scrimmage represented out-group and in-group treatments, respectively. Results revealed that testosterone showed (...) no measurable change. DHEA increased during both treatments in the majority of participants and the degree of change had no relation to independent variables or covariate measures. Most boys experienced androstenedione increases during match play, but no significant differences during the intrasquad soccer scrimmage competitions. The magnitude of change differed significantly between treatments and was positively associated with age. These latter findings suggest boys’ androstenedione responses may be sensitive to competitor type. For most subjects, cortisol significantly increased during match play, decreased during the intrasquad soccer scrimmage, and differed significantly between treatments, suggesting each treatment promoted a different psychological state among competitors. Cortisol/DHEA molar ratio decreased during the intrasquad scrimmage, suggestive of a more relaxed mental state. These data shed new light on potential proximate mechanisms associated with coalitional competition among prepubescent boys, with relevance to adrenarche and life history theory. (shrink)

The principles of sexual selection were used as an organizing framework for interpreting cross-national patterns of sex differences in mathematical abilities. Cross-national studies suggest that there are no sex differences in biologically primary mathematical abilities, that is, for those mathematical abilities that are found in all cultures as well as in nonhuman primates, and show moderate heritability estimates. Sex differences in several biologically secondary mathematical domains are found throughout the industrialized world. In particular, males consistently outperform females in the solving (...) of mathematical word problems and geometry. Sexual selection and any associated proximate mechanisms influence these sex differences in mathematical performance indirectly. First, sexual selection resulted in greater elaboration in males than in females of the neurocognitive systems that support navigation in three-dimensional space. Knowledge implicit in these systems reflects an understanding of basic Euclidean geometry, and may thus be one source of the male advantage in geometry. Males also use more readily than females these spatial systems in problem-solving situations, which provides them with an advantage in solving word problems and geometry. In addition, sex differences in social styles and interests, which also appear to be related in part to sexual selection, result in sex differences in engagement iii mathematics-related activities, thus further increasing the male advantage in certain mathematical domains. A model that integrates these biological influences with sociocultural influences on the sex differences in mathematical performance is presented in this article. (shrink)

We compared two digital humanities methods in the analysis of a contested scientific term. “Epigenetics” is as enigmatic as it is popular. Some authors argue that its meaning has diluted over time as this term has come to describe a widening range of entities and mechanisms (Haig, International Journal of Epidemiology 41:13–16, 2012). Others propose both a Waddingtonian “broad sense” and a mechanistic “narrow sense” definition to capture its various scientific uses (Stotz and Griffiths, History and Philosophy of the (...) Life Sciences 38:22, 2016). We evaluated these proposals by first replicating a recent analysis by (Linquist and Fullerton, Theoretical Medicine and Bioethics 42:137–154, 2021). We analyzed the 1100 most frequently cited abstracts on epigenetics across four disciplines: proximal biology, biomedicine, general biology, and evolution. Each abstract was coded for its heritability commitments (if any) and functional interpretation. A second study applied LDA topic modelling to the same corpus, thus providing a useful methodological comparison. The two methods converged on a discipline-relative ambiguity. Within such disciplines as biomedicine or molecular biology that focus on proximate mechanisms, “epigenetic(s)” refers to a range of molecular structures while specifying nothing in particular about their heritability. This proximal conception was primarily associated with the functions of gene regulation and disease. In contrast, a second relatively uncommon sense of “epigenetic(s)” is restricted to a small proportion of evolutionary abstracts. It refers to many of the same molecular structures, but regards them as trans-generationally inherited and associated with adaptive phenotypic plasticity. This finding underscores the benefit of digital tools in complementing traditional conceptual analysis. Philosophers should be cautious not to conflate the relatively uncommon evolutionary sense of epigenetics with the more widely used proximal conception. (shrink)