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Adverse Childhood Experiences (ACEs) are situated as the foundation of a six-tier pyramid, above which rests: (1) disrupted neurodevelopment; (2) social, emotional, and cognitive impairment; (3) adoption of health-risk behaviors; (4) disease, disability, and social problems; and (5) early death. ACEs purportedly initiate a causal sequence of negative developmental, behavioral, social, and cognitive outcomes, culminating in heightened mortality risk. Militating against this causal explanation, life history evolution is herein hypothesized to be the true foundation of any such pyramid. Subsuming ACEs within a life history framework has two broad implications: First, to some extent, ACEs are effectively changed from cause to correlate; second ACEs are seen as markers of strategic life history variation, not markers of dysfunction.

Background In 2020, about one in four women in Burkina Faso faced an unmet need for family planning (FP). Between 2013 and 2017, Burkina Faso implemented a performance-based financing (PBF) program to improve primary health care service provision (including FP) at rural health centers. Our prior work revealed that PBF did not lead to a reduction in unmet need for FP, in spite of FP being an explicitly targeted service. Our current study assesses supply-side factors that have likely contributed towards this lack of effect at population level, by examining changes in facility-based indicators relevant to the provision of FP induced by PBF. Methods We used facility-based survey data from 406 PBF and 117 control facilities collected before and after the PBF implementation. To compare changes in FP service provision, we examined changes in a number of relevant indicators including: a. the types of FP methods offered by facilities; b. trainings received by different FP providers; and c. available stocks of modern contraceptives. We relied on a difference-in-differences (DID) regression model to estimate the impact of PBF on these indicators. Results We observed a significant positive impact on the number of staff qualified to provide injectables, implants and IUDs (effect size 0.47, p 0.003) as well as the number of facilities offering IUDs (effect size 0.28, p 0.016) and a significant reduction in the number of facilities experiencing stock-outs of female condoms (effect size -0.09, p 0.007) and implants (effect size -0.03, p 0.042). Conclusions Given the significant positive impacts on the number of qualified staff, facilities providing IUDs and a reduction in stock-outs of female condoms and implants attributable to the PBF intervention without showing signs of negative effects on the indicators measured supply-side factors might not have been the main reason for the lack of effect of the PBF program on unmet need for FP. Key messages • Supply-side factors might not have been the main reason for the lack of effect of the PBF program on unmet need for FP. • Further research is needed to explore other potential underlying reasons.

After many waves of out-migration from Africa, different human populations evolved within a great diversity of physical and community ecologies. These ambient ecologies should have at least partially determined the selective pressures that shaped the evolution and geographical distribution of human cognitive abilities across different parts of the world. Three different ecological hypotheses have been advanced to explain human global variation in intelligence: (1) cold winters theory (Lynn, 1991), (2) parasite stress theory (Eppig, Fincher, & Thornhill, 2010), and (3) life history theory (Rushton, 1999, 2000). To examine and summarize the relations among these and other ecological parameters, we divided a sample of 98 national polities for which we had sufficient information into zoogeographical regions (Wallace, 1876; Holt et al., 2013). We selected only those regions for this analysis that were still inhabited mostly by the aboriginal populations that were present there prior to the fifteenth century AD. We found that these zoogeographical regions explained 71.4% of the variance among national polities in our best measure of human cognitive ability, and also more concisely encapsulated the preponderance of the more specific information contained within the sampled set of continuous ecological parameters.

Life history strategy represents individual variation in the degree to which bioenergetic resources are allocated toward growth, maintenance, and reproduction. Individual differences in life history strategies are thought to underlie many of the individual differences studied in Psychology. It was hypothesized that responses on the Sentence Completion Test of Ego Development are partially reflective of an individual’s life history strategy. This hypothesis was tested in three studies, each representing a different level of analysis. The results of Study 1 suggest near unity between ego-level and life history strategy at the conceptual level. In Study 2 a moderate association between rated ego-level and rated life history strategy was found. Additional analyses showed that this association remained when controlling for verbal IQ and that developmental change in each construct was correlated. In Study 3, it was found that responses to the sentence stems could be used directly to assess life history strategy. Combined, the results add to the evidence that responses on projective tests using a sentence stem format are associated with life history strategy. Future research could focus on identifying and constructing sentence stems that provide the maximum information about an individual’s life history strategy.

Background Levetiracetam (LEV) is one of the most frequently used antiepileptic drugs (AED) for brain tumor patients with seizures. We hypothesized that toxicity of LEV and temozolomide-based chemoradiotherapy may overlap. Patients and Methods In a retrospective analysis of individual patient data using a pooled cohort of patients with newly diagnosed glioblastoma included in clinical trials prior to chemoradiotherapy (CENTRIC, CORE, AVAglio) or prior to maintenance therapy (ACT-IV), we tested associations of hematologic toxicity, nausea or emesis, fatigue, and psychiatric adverse events during concomitant and maintenance treatment with the use of LEV alone or with other AED versus other AED alone or in combination versus no AED use at the start of chemoradiotherapy and of maintenance treatment. Results Of 1681 and 2020 patients who started concomitant chemoradiotherapy and maintenance temozolomide, respectively, 473 and 714 patients (28.1% and 35.3%) were treated with a LEV-containing regimen, 538 and 475 patients (32.0% and 23.5%) with other AED, and 670 and 831 patients (39.9% and 41.1%) had no AED. LEV was associated with higher risk of psychiatric adverse events during concomitant treatment in univariable and multivariable analyses (RR 1.86 and 1.88, p Conclusion Any association of psychiatric adverse events with LEV did not persist beyond the concomitant treatment phase. Antiemetic properties of LEV may be beneficial during the maintenance temozolomide.

This is the first of five papers celebrating the psychological complexity of nineteenth century Russian novels authored by Alexander Sergeyevich Pushkin, Nikolai Vasilievich Gogol, Lev Nikolayevich Tolstoy, Fyodor Mikhailovich Dostoyevsky, and Ivan Sergeyevich Turgenev. Using biography, letters, narratives, and literary criticism, the life and writings of each author will be reviewed as they contribute to the understanding of the human mind and the apperception of the human condition. More subtly than the case study, more fully than the clinical anecdote, more profoundly than the apt example, these novels animate sterile, empirical findings and add dimension to the flatness all too prevalent among psychological description. Herein, Pushkin’s tempestuous upbringing, cavalier belligerence, and eccentric oddities show that the Russian author, as much as his work, sustains and rewards close psychological study.

Differential-K theory, when applied to the study of anxiety disorders, predicts that slower life history (LH) racial groups exhibit higher levels of trait anxiety and worry, and higher prevalence of anxiety disorders, as both LH and anxiety experiences are future oriented. We predict that slower LH racial groups will exhibit an especially high prevalence of those anxiety disorders in which: (A) A central symptom is excessive worry rather than the anxious emotion only, as worry is an effortful cognitive phenomenon that involves mentally scrutinizing longer-term future threats and solutions; and (B) The central source of concern is social interactions, as the long-term maintenance of social relationships is one of the hallmarks of slow LH. We conducted an extensive search in international databases of scientific publications, with selection criteria chosen to reduce the possible effect of methods variance in the design and language of psychometric instruments and protocols, as well as variance in psychological health services and sociopolitical conditions. In line with the evolutionary hypothesis, Whites exhibited a higher prevalence of worry-related and sociality-related anxiety disorders than African-Americans and Latinos. Self-report data on worry and social anxiety traits further supported the evolutionary hypothesis, with Northeast Asians reporting the highest average scores. Importantly however, Blacks exhibited higher rates of post-traumatic stress disorder, a stressor-related condition, lending partial support to the social psychology hypothesis. We review and discuss racial differences in propensity to seek professional help when experiencing distress, in emotional expression to health care workers, and in the validity of psychometric measures, and conclude they are unlikely explanations for the identified race differences. Future studies that test the evolutionary hypothesis on differences among populations within these broad racial groupings are necessary to further examine the predictive power of this theory.

Commentary on the American Museum of Natural History’s Hall of Human Origins often omits a closing exhibit wherein three scientists speak about the nature of faith and evolutionary science. Two prior reviews of this exhibit criticize an effort to conciliate patrons and avoid controversy, a charge that is, in part, substantiated by an accompanying plaque disclaiming any inherent conflict between “scientific explorations into the material world and a spiritual search for the meaning of human existence.” Written plaques are reinforced by three scientists on continuous loop, two of whom are professed Christians whose views might be faulted for abstracting humans from the animal kingdom, granting to religious metaphysics what has been explained by evolution, and implying a purposeful teleology where none exists. Eschewing these points of criticism, this paper pursues the divide between the exhibit’s conciliation and scientific opinion. Inclusion of two prominent theistic evolutionists implicitly biases...

Whole books, and sections of books, have been dedicated to reviewing the intellectual history of multilevel selection, some small swath of which are considered in this first chapter. Readers are then made aware of other pertinent publications, acquiring something of their substance in this condensed review. For example, readers will certainly gain knowledge of multilevel selection’s prototypical origins as they are present in Darwin’s Descent of Man, while also being introduced to its reformulation a century later as a measure of population regulation. In addition to preferring main ideas to tortuous detail, we here take such content’s subsequent relevance as our litmus test for inclusion. We also review recent bouts of controversy between adherents and detractors. Where historical review is the end of other books, we use the history of multilevel selection instrumentally, with the end of contrasting its original formulation with its present instantiation. Having drawn these distinctions, one can clearly see that most controversies and objections no longer apply, as they do not pertain to modern manifestations of multilevel selection. Even as naysayers continue to criticize it for something it either never was or no longer is, the modern formulation of multilevel selection is becoming known to, and accepted among, most evolutionists. Nevertheless, this is only the first act in the two-part drama, taking us to the lowest ebb of multilevel selection’s reputation. The astute reader may notice that we use the expression multilevel selection when referring to the more general theoretical framework that is the subject matter of the present volume, while reserving the term group selection for describing the positions of past commentators that directed their reflections specifically to this particular component of multilevel selection theory, especially as more narrowly defined by past formulations of this principle. Multilevel selection theory is a more inclusive term that recognizes the operation of selection at multiple levels of biological organization, including both solitary individuals and social groups, as exemplified but never explicitly named by Charles Darwin’s thinking on the matter.

The previous chapter depicted a rising chorus of consensus starting in the 1970s. Sober and Wilson describe how group selection was buried in the 1960s and 1970s and treated with utter contempt. It was so reviled that it was not forgotten, but recalled as an example of how not to think. Even in the 1980s, as Sober and Wilson recount, an unidentified, distinguished biologist once advised a younger colleague that there are three things that one does not defend in biology: group selection, phlogiston theory, and Lamarckian evolution. Indeed, discussion of group selection, at certain points in the history of evolutionary biology, evoked criticism and even ostracism, as illustrated by the following reflection shared by the still skeptical professor Detlef Fetchenhauer (2009)

As exemplified by the history of the Roman State, economic distress can decrease the level of intrasocietal cohesion even in the absence of external pressures. Since its inception, the Roman Republic faced numerous foreign threats, from rival cites in the Italian peninsula to tribal confederacies in Gaul. A chronic state of intergroup conflict favored the evolution of cultural variants necessary for sustaining large-scale cooperation. These innovations allowed the Republic to conquer its neighbors and expand outside the Italian peninsula. Even though the spoils of war created a climate of macroeconomic prosperity in Rome, the rising income and wealth inequality, along with the elimination of ultrasocial institutions, increased popular discontent. It was during these times of turmoil that ambitious men dismantled the foundations designed to guard the State from the exploitation of autocrats. Debates concerning land and wealth distribution, at first restricted to senatorial rhetoric, escalated into street revolts and political assassinations. The mobilization of “private armies,” as part of a series of civil wars, would eventually lead to the end of the Republic.

This chapter is the first of five comprising Part III. Though, as in Chap. 6, we have previously allowed some lexical analyses to interpolate Part II’s historical-empirical thrust, Part III is predominately statistical, even as it continues to review relevant literature and history. Though, consistent with the mandate of this monograph, we aim ultimately to establish the reality of human group selection, this initial chapter alone treats chimpanzees. To thoroughgoing evolutionists, the relevance will be self-evident; we only add that establishing evidence of group selection in such a highly related species foundationally supports the empirical argument for human group selection, as presented in the four subsequent chapters constituting Part III of this volume.

This chapter will provide a synthesis of the current evolutionary literature concerning lethal coalitional aggression in small-scale societies. Attacks, raids, skirmishes, ambushes, and other forms of intergroup aggression present significant risk of injury or death, irrespective of group size, though the means of differentiation among groups, like the mechanisms of ensuring coordination within groups, change as a function of group size. Human coalitional violence is often explained via kin selection and reciprocal altruism, such that an individual’s assumption of risk is compensated by fitness-enhancing benefits to relatives and allies. These explanations become increasingly inapplicable in progressing from bands and tribes to chiefdoms and states. The growth of larger social aggregations compelled the emergence of institutions enforcing intragroup cooperation above and beyond the effects of underlying social networks based on kinship and direct reciprocity. Perspectives reviewed herein, such as cultural group selection, consider the cultural evolution of such institutions in generating between-group variance and facilitating lethal intergroup competition. According to these theories, cultural transmission, group differentiation, symbolic ornamentation, punishment of defectors, and ethnocentrism are integral components of intergroup competition, with lethal coalitional aggression being an extreme manifestation of between-group rivalry. Furthermore, due to the significant fitness costs imposed upon defeated factions, the study of lethal coalitional aggression in small-scale societies provides fertile ground for examining the interaction between group-level and individual-level selective pressures.

The subject of societal collapse is a theme that, due to its political, social, economic, and ecological implications, still generates heated discussions. Researchers interested in developing a general theory of collapse face the challenge of identifying common patterns across human societies. This task is further complicated because multiple publications on the subject employ a case-by-case methodology, within which the causes of collapse are thought to be specific to each society. Such historical particularism persists to this day. Historical contingency is preferred to generalizable explanation. In response, some researchers have instead concentrated on examining how a society’s internal dynamics predict the risk of collapse. For example, a society’s institutional performance, macroeconomic yields, and level of collective action have been thought predictive of its structural integrity under adverse circumstances. Through this lens, external factors may lead to a sudden loss of sociopolitical complexity only when the system’s capacity to address these conditions is compromised. Given variation in societies’ level of cohesion and collective action, the case of societal collapse offers a unique glimpse into multilevel selection operating among social systems. This chapter describes critical elements developed in the collapse literature while providing an overview of the current multilevel selection perspectives on fluctuations in collective action. The present chapter also describes how institutional robustness and cultural innovations contribute to a society’s regeneration capacity after experiencing a collapse.

The content of the previous two chapters described mathematical models and presented relevant empirical data pertaining to multilevel selection as a proposed biological universal within the general framework of evolutionary theory. The present chapter turns to phenomena that are believed to apply more specifically to humans. Consistent with the Darwinian principle of continuity, we are not claiming that humans stand alone as somehow separate from the rest of animal nature, given that the differences between human and nonhuman animals are most often differences in degree and not in kind. Nevertheless, there is also a case to be made that all species are to some extent unique and distinguishable from each other based on species-typical characteristics. Following from the principle of continuity, humans are not excepted from the forces of multilevel selection. Nevertheless, humans are unique by virtue of our species-typical characteristics, and so have a unique relationship to multilevel selection deriving from our unique evolutionary history. If we infer correctly, Wilson (2015) concurs with this assessment, figuring among those few authors who recognize the human species as having been particularly susceptible to multilevel selection throughout our evolutionary history. As an explanatory framework, multilevel selection might therefore be most interesting, elaborate, and probable among human populations precisely for the many complex qualities that qualify as human. This section, and all the sections that follow within this chapter, can then be understood to explore the unique properties of humans, both as they were shaped by multilevel selection and as they allowed multilevel selection to assume unprecedented effects and directions. In sum, when simultaneously considering the aforementioned principle of continuity alongside species-typical human universals, one finds certain principles of multilevel selection uniquely applicable to our species and not many others. To fulfill this mandate, we provide prerequisite knowledge of cultural evolution theories, gene-culture coevolution, and cultural group selection before closing with an integrated section embedding group selection within the larger framework of multilevel selection theory.

This chapter and the three that follow collectively comprise Part II of our book, respectively, entitled “Aggregation, Growth, Decline, and Collapse.” Thus, these four chapters collectively comprise a theme familiar to declinists and students of cyclical history. As will be reiterated in later chapters, each of these processes must be studied in abstract after the manner of traditional scholarship, as has been pursued by Gibbon, Vico, Toynbee, Ibn Khaldun, and Spengler. However, it will also be important to update some of the theories proposed by these past historians with subsequent discoveries. Furthermore, as this is a book on multilevel selection, we separately and systematically consider the influence of group-selective pressures as they contribute to aggregation and state formation, the decline of mature civilizations, and their eventual collapse.

Where Chap. 4 reviewed the formation of sociopolitically complex civilizations, this chapter reviews their growth and maintenance. Mature states invariably come to encompass expanding territories and consequently absorb populations distinct in dialect and language, ethnicity and race, and culture and religion. As discussed herein, maintaining integrity at a particular level of group size comes from managing both sources of threat: managing one’s own population while defending against rival groups. Populations must be bound by some combination of custom, sanctions, religion, and legal infrastructure. To the extent that this can be accomplished, a state must radiate control stably through time, as indicated by the Roman Empire and contraindicated by the conquests of Alexander the Great. Controls necessary for stable growth can be (1) psychological, as with propaganda; (2) legal, as with incarceration; (3) social, as with banishment; (4) martial, as with conscription; or (5) economic, as with taxation. Some controls woo and win elites, ensuring allegiance through shared interest, title, rank, privilege, estates, orders, and garters. With reliable money as a medium of exchange, states ensnare citizens within a tightening cage of mutual interest, trade, dependencies wrought of divided labor, and the attractive ability to solve collective action problems. All such forms of control foster growth and allow for societal maintenance.

In 2017, our research team produced a technical, statistically driven, monograph entitled The Rhythm of the West: A Biohistory of the Modern Era, AD 1600 to the Present. Therein, general intelligence, life history, and other topics were treated alongside multilevel selection theory. Here, after providing a general overview for the sake of context, we extract findings and discussion points from The Rhythm of the West directly relevant to demonstrating the reality of group selection within the history of the Britannic peoples. In a colloquial and qualitative manner, displaying essential analyses and separated from ancillary topics, we explain group selection among the Britannic peoples as they have transitioned through stages of expansion, fission, and decline. Wealth, cognitive capacity, subjective well-being, poverty, and longevity are among the oblique markers of civilizational pulse. These correlate with, and are corroborated by, demographic decline. Declining evolutionary pressures for group-selected behaviors within mild industrial and postindustrial environments, operating for generations, have had a causal role in population decline, both in absolute and relative terms. To describe and explain the aforementioned decline, we review a variety of changes to Europe’s Early Modern Era selective regime, including climatic changes during the Little Ice Age, niche expansion and modification during the Age of Exploration, nutritional advances gained during the British Agricultural Revolution, and technological advances gained during the Industrial Revolution.

Chandler, Lalonde, Sokol, and Hallett created the Personal Persistence Interview in an effort to determine how persons defend their sense of personal persistence. In other words, these researchers wanted to determine the means by which one’s present self and past self can remain subjectively similar in spite of change. A modified version of that research tool is presently used to obtain narratives not only of personal persistence but also of its absence. As of yet, there are no open-ended descriptions of how and why one’s past and present self-experience could be wholly different. These narratives are colloquially presented as they relate to change, time, and culture. Maturation and perspectival changes putatively induced more than half the sample of 177 college-aged participants to report an absence of personal persistence. Still, others, also acknowledging substantial change, continued to feel personally persistent. Change within early and late modernity, as well as change as it is expressed in theories of self, will be compared with change as it is present in these life narratives.

Size at birth, growth rate, age at sexual maturity, number and size of offspring, and longevity are among the variables studied in life history evolution, a mid-level branch of evolutionary biology. Long-lived, slow maturing, and highly encephalized Homo sapiens, though skewed as a group towards the very slow end of the spectrum, nevertheless show some life history variation; variation which may relate to, and to some extent explain, personality variation. When applied to extant personality disorders, the risk-taking, boldness, and impulsivity of psychopathy is explained as a fast life history strategy. Herein, it is argued that the highly heritable obsessive-compulsive personality disorder (OCPD), opposite psychopathy, is a slow life history strategy. Both OCPD and slow life history strategists exhibit anxiety and harm avoidance, risk and loss aversion, future-oriented thought and time urgency, delayed gratification, and conscientious labor and fidelity. In addition to a host of compelling correlations, the preponderance of intrinsic over extrinsic mortality that explains the evolution of slow life histories is precisely that which has been described in an ecological etiology that explains OCPD as a product of post-migration evolution from Africa into Eurasia.

DSM-V estimates the prevalence of Obsessive Compulsive Personality Disorder (OCPD) to fall between 2.1 and 7.9 percent, making it one of the most prevalent personality disorders in the general population. Yet, obsessive prevalence is reported without its significance being appreciated. After reviewing the estimates of several studies, this paper pursues the theme of obsessive prevalence, showing why it was ignored, how it changes etiological assumptions, and, in turn, how newly generated etiologies engender the understanding of obsessive prevalence. High prevalence, when paired with high heritability, undermines psychoanalytic etiologies and invalidates psychiatric classification, suggesting that OCPD is a rare type, rather than a common disorder. Following this, evolutionary theory is used to illustrate the conditions from which this rare phenotype arose, and the mechanistic laws that maintain it within its present proportions. As treated within the discussion section, high prevalence, when contextualized within an evolutionary explanatory paradigm, suggests an ecologically determined biogeography of OCPD.

Introductory psychology classes and texts invariably feature attachment theory, which is rightly regarded as a pillar of the field. The acknowledged founder of attachment theory, John Bowlby, resisted the tide of psychoanalysis and instead pursued a more biological explanation of parent–child relations, characterized by insecure attachment variants as dysfunctional miscarriages of mother–infant bonding. Contrary to Bowlby’s assumptions, the supposed pathology of the insecure attachment is reframed by life history evolution as strategic adaptation to reproductive ecologies. While insecure attachment is not specifically adaptive, eliciting rearing behaviors displayed by parents, like early sexual debut, mate diversity, completed fertility, and other resultant mating behaviors displayed by the child at maturity, are adaptive within unpredictable and stochastic environments.

In his Atlas of World Cultures, George Murdock catalogues more than 1000 discreet populations of peoples that are too often amalgamated at the level of the nation-state. For each of these ethnically informed cultural populations, Murdock provides nearly fifty points of tabular ethnographic codes, including mating systems, kinship networks, levels of consanguinity, post-marriage living arrangements, type and intensity of agriculture, settlement patterns, and social fluidity, which are then combined with environmental statistics such as latitude, and primary and secondary climate classifications. This chapter asks and answers questions concerning Galton’s Problem, finding commonalities among contiguous cultures to extend, not simply from contiguity, but from shared selective pressures. Murdock’s cross-cultural classificatory variants therefore derive from ecologically driven evolution, as described in social biogeographical applications of life history theory.

Like Toynbee, William McNeill is a world historian, but one with a bent toward epidemiology. Most directly in his Plagues and Peoples, McNeill considers the role of disease-induced mortality, infection, and transmission alongside the more traditional historical topics of war and conquest. McNeill studied disease as a primary cause in its own right, rather than as incidental sequelae to climatological catastrophes, famine, war, or resource limitation. McNeill anticipates the emphasis placed by modern evolutionary life history theory upon regimes of extrinsic mortality as being the main drivers shaping life history evolution. After all, from its founding, life history has incorporated population density and mortality rates into its quantitative formulae and qualitative theory, making it an ideal framework from which to reconsider McNeill.

Written over decades, subsuming much of his career as a sociologist, Michael Mann’s four-volume Origins of Social Power pursues one grand theme: Societal aggregation from tribe, to fief, to city-state, to nation, to empire. Mann uses the term, “patterned mess,” in recognition of cultural, historical, and temporal particularities which overlay sociological laws as they have operated through time. Modern theories of gene–culture coevolution work precisely in this way, in that they operate on a fundamental level, even as surface features vary. So when Mann studies internal divisions and external competition as they ebb and flow creating regression and progression along this continuum of aggregation, it is now possible to partially explain this as a function of variation across aggregate life history continua.

Bound together by virtue of their shared mission to explain human nature and society, the social sciences have unity of purpose even as they have no meta-theory; there exists no foundation from which variables can be connected, causally sequenced, or ultimately explained. By way of an overview in abstract, this first chapter introduces life history theory, the meta-theoretical pretentions of which are demonstrated during the remainder of the book by reading geographers, demographers, historians, anthropologists, sociologists, and psychologists in life history evolutionary perspective. Thereafter, comes a survey of the anatomical structure common to the eighteen core chapters, which are divided into four parts, beginning with an overview and concluding with a theoretical proof. These core chapters are grouped into six sections, each ending with a meta-commentary.

With eminently unpropitious timing, Thomas Robert Malthus wrote of resource competition just as humans were bursting the bonds of organic economies. An Essay on the Principle of Population, in warning of the ills consequent to population density and resultant resource competition, may have, however, underappreciated its evolutionary effects. Although the significance of mortality regime has superseded its overall significance, population density, and the resource competition it brings, was the variable around which life history theory was originally constructed. With the coming of density and accompanying competition, life history theory explains how populations change and stratify as they vie to survive and reproduce. As herein argued, the slowing of life history is a consequence of population density that Malthus could not suspect, but might have appreciated.

Montesquieu incorporates what would now be understood as political science and ecology into his eighteenth-century sociological studies. He concluded that sociopolitical systems were outgrowths of ecological conditions, and so cannot be unthinkingly transplanted from locale to locale. Already extant, there are evolutionarily informed studies of Montesquieu’s thesis using variables such as group-mean intelligence, which validates the relation between ecology and the development of monarchies, republics, and despotisms. However, this fourteenth chapter shows that this is but a part of a larger process. Human populations respond to ecological conditions through changes in mean intelligence, but also through changes in other life history traits. Consequently, it is inter-population life history means that were obliquely observed by Montesquieu to give rise to sociopolitical differences.

Through his Bioecological Systems Theory, Urie Bronfenbrenner emphasized school, parish, neighborhood, and other aspects of what behavioral geneticists now call the extra-familial environment. Bronfenbrenner incorporated even the economy, government, and culture into his developmental scheme, knowing that these macrostructural realities trickle-down to influence more local systems, if not the child directly. As recounted in this chapter, life history theorists have extended ecological systems theory such that it incorporates natural ecological systems, not limited to temperature, humidity, parasite prevalence, resource availability, and population density. An evolutionary view of Bronfenbrenner’s Ecological Systems Theory then clarifies the extent and direction of influences, while also adding a basement layer of natural ecology that constrains all other levels of influence.

In the late Victorian era, one could find Ellsworth Huntington caravanning through Eurasia, counting tree rings in northern California, or subsisting on stipends on the fringes of Yale’s geology department. Writing on demography as much as geography, Huntington described non-random change through founding effects and migration, as much as natural and sexual selection. Importantly, he distinguished between physical and community ecology, applying these concepts to human biogeography. Though not available to Huntington who wrote most prolifically in the earliest part of the twentieth century, life history evolution is indispensable to understanding the dynamics of climatically induced evolution across populations treated, for instance, in The Principles of Human Geography and The Human Habitat. Through Huntington’s writings, cross-continental variation in life histories is introduced and explained.

Raymond Cattell distinguished crystallized intelligence, akin to stored knowledge, from fluid intelligence, akin to raw reasoning abilities. Likewise, he delineated personality into component parts. Though intelligence and personality each qualify as subdisciplines within psychology, both are subsumed, along with other traits, under the meta-theory of life history evolution. The relationship is profound, though not straightforward. As described in this chapter, both intelligence and personality vary along a life history continuum, such that, as life history slows, population mean intelligence increases, as do personality traits like risk aversion, conscientiousness, anxiety, and agreeableness. Nevertheless, this effect occurs on average, and there is strategic variation occurring, which obscures the relationship between population-mean intelligence, personality, and life history. Once understood, these relationships color and clarify Cattell’s life’s work.

James Casey researches regional variation in lineal descent, consanguinity, and patterns of inheritance as they alternately impede or impel state formation. Joined by a spirit of capitalism, a market economy, and the division of labor, lineal descent, consanguinity and patterns of inheritance each had a role to play as drivers of state formation, and markers of progress toward social complexity. To the degree that kinship bands persisted, they acted simultaneously as an impediment to autonomous household formation, and to formal state formation. As Casey contends, changes in family organization underlay changes in social organization. Building upon this insight, as this tenth chapter describes, precipitating ecological drivers and concomitant evolutionary consequences cannot be absented when explaining the historical transition from consanguineous tribe to genetically diversified state.

Alan Baker’s work documents the fulfillment of the Neolithic Revolution with its mature societies resting on a foundation of staple grain crops. In Studies of Field Systems in the British Isles, Baker studies agriculture and its laboring class, while in Man Made the Land, he takes up the social outgrowths of agriculture. As evident in Baker’s studies of the French and English peasantry, much of the social changes following from agriculture are corollaries of population density. We interpret the technological advances, cooperation, and civilization as described by Baker, as outward manifestations of slowing life histories evolving through to historical time. Thus, Baker is eminently correct to assert that geography has shaped human history, even as he may not have been thinking of evolutionary history.