Childhood environmental harshness predicts coordinated health and reproductive strategies: A cross-sectional study of a nationally representative sample from France

Metabolic trade-offs in childhood: Exploring the relationship between language development and body growth

During human childhood, brain development and body growth compete for limited metabolic resources, resulting in a trade-off where energy allocated to brain development can decrease as body growth accelerates. This preregistered study explores the relationship between language skills, serving as a proxy for brain development, and body mass index at three distinct developmental stages, representing different phases of body growth. Longitudinal data from 2002 children in the EDEN mother-child cohort were analyzed using structural equation modeling. Our findings reveal a compelling pattern of associations: girls with a delayed adiposity rebound, signaling slower growth rate, demonstrated better language proficiency at ages 5-6. Importantly, this correlation appears to be specific to language skills and does not extend to nonverbal cognitive abilities. Exploratory analyses show that early environmental factors contributing to enhanced cognitive development, such as higher parental socio-economic status and increased cognitive stimulation, are positively associated with both language skills and the timing of adiposity rebound in girls. Overall, our findings lend support to the existence of an energy allocation trade-off mechanism that appears to prioritize language function over body growth investment in girls.

Specifying the timescale of early life unpredictability helps explain the development of internalising and externalising behaviours

Early life unpredictability is associated with both physical and mental health outcomes throughout the life course. Here, we classified adverse experiences based on the timescale on which they are likely to introduce variability in children's environments: variations unfolding over short time scales (e.g., hours, days, weeks) and labelled Stochasticity vs variations unfolding over longer time scales (e.g., months, years) and labelled Volatility and explored how they contribute to the development of problem behaviours. Results indicate that externalising behaviours at age 9 and 15 and internalising behaviours at age 15 were better accounted for by models that separated Stochasticity and Volatility measured at ages 3 to 5. Both externalising and internalising behaviours were specifically associated with Volatility, with larger effects for externalising behaviours. These findings are interpreted in light of evolutionary-developmental models of psychopathology and reinforcement learning models of learning under uncertainty.

The Effect of Income and Wealth on Behavioral Strategies, Personality Traits, and Preferences

Individuals living in either harsh or favorable environments display well-documented psychological and behavioral differences. For example, people in favorable environments tend to be more future-oriented, trust strangers more, and have more explorative preferences. To account for such differences, psychologists have turned to evolutionary biology and behavioral ecology, in particular, the literature on life-history theory and pace-of-life syndrome. However, critics have found that the theoretical foundations of these approaches are fragile and that differences in life expectancy cannot explain vast psychological and behavioral differences. In this article, we build on the theory of optimal resource allocation to propose an alternative framework. We hypothesize that the quantity of resources available, such as income, has downstream consequences on psychological traits, leading to the emergence of behavioral syndromes. We show that more resources lead to more long-term orientation, more tolerance of variance, and more investment in low marginal-benefit needs. At the behavioral level, this translates, among others, into more large-scale cooperation, more investment in health, and more exploration. These individual-level differences in behavior, in turn, account for cultural phenomena such as puritanism, authoritarianism, and innovation.

Early life adversity jointly regulates body-mass index and working memory development

Previous work has proposed that balancing energy expenditure towards body and brain development in an optimal fashion results in a negative relationship between somatic and neurocognitive growth during development. An important issue, largely overlooked so far, is the extent to which this energetic trade-off is influenced by early life environmental factors. In this study, we estimated the association between neurocognitive (measured by working memory ability) and somatic (measured by body-mass index) developmental trajectories, while taking into account multiple dimensions of early life adversity. Results of our initial growth curve model were consistent with this brain-body trade-off in both girls and boys. In a subsequent model, we showed that early life adversity had positive associations with somatic and negative associations with neurocognitive growth trajectories, although the direct negative coupling between them remained consistent. Finally, a multidimensional adversity model, separating the effects of deprivation, threat and unpredictability, revealed that the dimension of deprivation-reflecting lack of access to resources and cognitive stimulation-contributed the most to both somatic and neurocognitive growth patterns. These results suggest that the way individuals balance energy between these two biological constructs during development is partly linked to environmental influences through phenotypic plasticity.

Childhood environmental harshness and unpredictability negatively predict eHealth literacy through fast life-history strategy

Background

eHealth literacy-the ability to obtain, understand, evaluate, and use health information from the Internet-is important to maintaining and improving personal health. Prior research found that people differ notably in the levels of eHealth literacy, and this study tests a theoretical account of some of those individual differences. Drawing on life history theory, we propose that low eHealth literacy is partly the outcome of people adopting a resource-allocation strategy emphasizing early and fast reproduction, namely, a fast life-history strategy.

Methods

We conducted a cross-sectional survey study (N = 1,036) that measured Chinese adult respondents' eHealth literacy, childhood environmental harshness and unpredictability, and fast life-history strategy. Covariates included health-information seeking online, self-rated health, sex, age, education level, and monthly income.

Results

Supporting a life-history explanation of eHealth literacy, childhood environmental harshness and unpredictability negatively predicted eHealth literacy through fast life-history strategy and mainly the insight-planning-control dimension of it. Harshness, not unpredictability, also directly and negatively predicted eHealth literacy after fast life-history strategy was controlled for.

Conclusion

Our findings suggest that the psychological mechanisms associated with human life-history strategies produce at least some of the individual differences in levels of eHealth literacy, including those related to neuroticism, socioeconomic status, self-rated health and social capital. Thus, a possible way to increase future generation's eHealth literacy and thereby their health is to reduce the harshness and unpredictability of the environment in which they grow up, thereby making them more likely to adopt a relatively slow life-history in their adulthood.

Retrospective Self-Reported Childhood Experiences in Enriched Environments Uniquely Predict Prosocial Behavior and Personality Traits in Adulthood

What features of people's childhood environments go on to shape their prosocial behavior during adulthood? Past studies linking childhood environment to adult prosocial behavior have focused primarily on adverse features, thereby neglecting the possible influence of exposure to enriched environments (e.g., access to material resources, experiences with rich cooperative relationships, and interactions with morally exemplary role models). Here, we expand the investigation of childhood environmental quality to include consideration of enriching childhood experiences and their relation to adult prosociality. In two cross-sectional studies, we found promising evidence that enriched childhood environments are associated with adult moral behavior. In study 1 (N = 1,084 MTurk workers), we adapted an existing measure of enriched childhood environmental quality for retrospective recall of childhood experiences and found that subjects' recollections of their enriched childhood experiences are distinct from their recollections of adverse childhood experiences. In Study 2 (N = 2,208 MTurk workers), we found that a formative composite of subjects' recollections of enriched childhood experiences is positively associated with a variety of morally relevant traits in adulthood, including agreeableness, honesty-humility, altruism, endorsement of the principle of care, empathic responding to the plights of needy others, and charitable donations in an experimental setting, and that these associations held after controlling for childhood environmental adversity, childhood socioeconomic status, sex, and age. We also found evidence suggesting that some, but not all, of the relationship between enrichment and adult prosociality can be explained by a shared genetic correlation. We include a new seven-item measure as an appendix.

Child attachment in adjusting the species-general contingency between environmental adversities and fast life history strategies

Extrinsic mortality risks calibrating fast life history (LH) represent a species-general principle that applies to almost all animals including humans. However, empirical research also finds exceptions to the LH principle. The present study proposes a maternal socialization hypothesis, whereby we argue that the more human-relevant attachment system adds to the LH principle by up- and down-regulating environmental harshness and unpredictability and their calibration of LH strategies. Based on a longitudinal sample of 259 rural Chinese adolescents and their primary caregivers, the results support the statistical moderating effect of caregiver-child attachment on the relation between childhood environmental adversities (harshness and unpredictability) and LH strategies. Our theorizing and findings point to an additional mechanism likely involved in the organization and possibly the slowdown of human LH.

Testing the empirical integration of threat-deprivation and harshness-unpredictability dimensional models of adversity

Recent dimensional models of adversity informed by a neurobiological deficit framework highlights threat and deprivation as core dimensions, whereas models informed by an evolutionary, adaptational and functional framework calls attention to harshness and unpredictability. This report seeks to evaluate an integrative model of threat, deprivation, and unpredictability, drawing on the Fragile Families Study. Confirmatory factor analysis of presumed multiple indicators of each construct reveals an adequate three-factor structure of adversity. Theory-based targeted predictions of the developmental sequelae of each dimension also received empirical support, with deprivation linked to health problems and cognitive ability; threat linked to aggression; and unpredictability to substance use and sexual risk-taking. These findings lend credibility to utility of the three-dimensional integrative framework of adversity. It could thus inform development of dimensional measures of risk assessment and exploration of multidimensional adversity profiles, sensitive to individual differences in lived experiences, supporting patient-centered, strength-based approaches to services.

Why and how does early adversity influence development? Toward an integrated model of dimensions of environmental experience

Two extant frameworks - the harshness-unpredictability model and the threat-deprivation model - attempt to explain which dimensions of adversity have distinct influences on development. These models address, respectively, why, based on a history of natural selection, development operates the way it does across a range of environmental contexts, and how the neural mechanisms that underlie plasticity and learning in response to environmental experiences influence brain development. Building on these frameworks, we advance an integrated model of dimensions of environmental experience, focusing on threat-based forms of harshness, deprivation-based forms of harshness, and environmental unpredictability. This integrated model makes clear that the why and the how of development are inextricable and, together, essential to understanding which dimensions of the environment matter. Core integrative concepts include the directedness of learning, multiple levels of developmental adaptation to the environment, and tradeoffs between adaptive and maladaptive developmental responses to adversity. The integrated model proposes that proximal and distal cues to threat-based and deprivation-based forms of harshness, as well as unpredictability in those cues, calibrate development to both immediate rearing environments and broader ecological contexts, current and future. We highlight actionable directions for research needed to investigate the integrated model and advance understanding of dimensions of environmental experience.

How do reproduction, parenting, and health cluster together? Exploring diverging destinies, life histories and weathering in two UK cohort studies

Life history theory researchers often assume reproductive, parenting and health behaviours pattern across a fast-slow continuum, with 'fast' life histories (typified by short lifespans, early maturation and investing in quantity over quality of children) favoured in poor quality environments and/or when resources are scarce. Some researchers further reduce this down to a simplistic 'fast' versus 'slow' dichotomy. Some of these ideas, with different theoretical motivations, are echoed in the 'diverging destinies' and 'weathering' frameworks developed in the social sciences. Whether clustering of reproductive, parenting and health traits exists has rarely been empirically tested, however. Using latent class analysis on data on mothers from the UK's Millennium Cohort (MCS) and Born in Bradford (BiB) studies, we explored whether reproduction and parenting traits clustered into 'diverging destinies', whether 'weathering' effects tied together health and reproduction, and whether all three domains were combined into either 'fast' vs 'slow' life histories, or into three groups more indicative of a fast-slow continuum. We leveraged ethnic diversity in these samples to examine four groups of mothers separately: 1. MCS White British/Irish (n = 15,423); 2. MCS Pakistani-origin (n = 923); 3. BiB White British (n = 3937); 4. BiB Pakistani-origin (n = 4351), and explored whether faster 'weathering' was evident amongst Pakistani-origin mothers. Both two and three class models emerged as potential descriptions of latent subgroups, potentially providing support for fast and slow life histories or a continuum of traits. However, response profiles provided only limited support for theoretical predictions of which traits should cluster together, with inconsistent and restricted clustering of traits both within and between the domains of reproduction, parenting, and health. In addition, trait clustering was more pronounced amongst White mothers and we found no clear evidence supporting faster 'weathering' amongst Pakistani-origin mothers; the observed clustering instead suggested that cultural constraints may influence linkages between traits. Our results therefore provide some limited support for models which suggest certain traits cluster together in predictable ways, but it is also clear that theoretical frameworks should not emphasise very rigid clustering of large numbers of traits and should allow for contextual influences on clustering.

The Cognitive, Ecological, and Developmental Origins of Self-Disturbance in Borderline Personality Disorder

Self-disturbance is recognized as a key symptom of Borderline Personality Disorder (BPD). Although it is the source of significant distress and significant costs to society, it is still poorly specified. In addition, current research and models on the etiology of BPD do not provide sufficient evidence or predictions about who is at risk of developing BPD and self-disturbance, and why. The aim of this review is to lay the foundations of a new model inspired by recent developments at the intersection of social cognition, behavioral ecology, and developmental biology. We argue that the sense of agency is an important dimension to consider when characterizing self-disturbances in BPD. Second, we address the poorly characterized relation between self-disturbances and adverse life conditions encountered early in life. We highlight the potential relevance of Life-History Theory-a major framework in evolutionary developmental biology-to make sense of this association. We put forward the idea that the effect of early life adversity on BPD symptomatology depends on the way individuals trade their limited resources between competing biological functions during development.

On the Incongruence between Psychometric and Psychosocial-Biodemographic Measures of Life History

In evolutionary psychology, it is customary to measure life-history via psychometric inventories such as the Arizona Life History Battery (ALHB). The validity of this approach has been questioned: it is argued that these measures are not congruent with biological life history events, such as the number of children, age at first birth, or pubertal timing. However, empirical data to test this critique are lacking. We therefore administered the ALHB to a convenience sample of young adults in Serbia (N = 447). We also collected information on psychosocial-biodemographic life history parameters closely related to biological life history traits: pubertal timing, onset of sexual behavior, short- and long-term mating, number of children, timing of reproduction, parenthood values, and environmental harshness. We found that correlations between these two sets of measures were rare, unsystematic, and mostly low in magnitude. Stable patterns of relations emerged only between the indicators of environmental conditions from both sets of measures. Furthermore, some ALHB indicators were found to be positively related with early fertility, which is incongruent with the conceptual foundation of ALHB. Finally, network analysis and factor analysis within each set of measures revealed different structures and that the hypothesis of unidimensionality, on which the ALHB was founded, cannot be applied to psychosocial-biodemographic life history indicators. Our results support the critique of ALHB as a set of measures lacking validity to capture biodemographic life-history parameters. ALHB measures are indeed relevant for understanding life-history variation, but they cannot be used as a substitute for specific life history characteristics. Our findings are a warning to researchers to use direct measures of biological events in order to measure life-history dynamics.

Childhood environmental adversity is not linked to lower levels of cooperative behaviour in economic games

Cooperation is a universal phenomenon, it is present in all human cultures from hunter-gatherers to industrialised societies, and it constitutes a fundamental aspect of social relationships. There is, however, variability in the amount of resources people invest in cooperative activities. Recent findings indicate that this variability may be partly explained as a contextually appropriate response to environmental conditions. Specifically, adverse environments seem to be associated with less cooperation and recent findings suggest that this effect is partly mediated by differences in individuals' life-history strategy. In this paper, we set out to replicate and extend these findings by measuring actual cooperative behaviour in three economic games - a Dictator game, a Trust game and a Public Goods game - on a nationally representative sample of 612 people. Although we found that the cooperation and life-history strategy latent variables were adequately captured by the models, the hypothesised relationship between childhood environmental adversity and adult cooperation and the mediation effect by life-history strategy were not found.

Accelerated reproduction is not an adaptive response to early-life adversity in wild baboons

In humans and other long-lived species, harsh conditions in early life often lead to profound differences in adult life expectancy. In response, natural selection is expected to accelerate the timing and pace of reproduction in individuals who experience some forms of early-life adversity. However, the adaptive benefits of reproductive acceleration following early adversity remain untested. Here, we test a recent version of this theory, the internal predictive adaptive response (iPAR) model, by assessing whether accelerating reproduction following early-life adversity leads to higher lifetime reproductive success. We do so by leveraging 48 y of continuous, individual-based data from wild female baboons in the Amboseli ecosystem in Kenya, including prospective, longitudinal data on multiple sources of nutritional and psychosocial adversity in early life; reproductive pace; and lifetime reproductive success. We find that while early-life adversity led to dramatically shorter lifespans, individuals who experienced early adversity did not accelerate their reproduction compared with those who did not experience early adversity. Further, while accelerated reproduction predicted increased lifetime reproductive success overall, these benefits were not specific to females who experienced early-life adversity. Instead, females only benefited from reproductive acceleration if they also led long lives. Our results call into question the theory that accelerated reproduction is an adaptive response to both nutritional and psychosocial sources of early-life adversity in baboons and other long-lived species.

Do Criminals Live Faster Than Soldiers and Firefighters? : A Comparison of Biodemographic and Psychosocial Dimensions of Life History Theory

A high risk of morbidity-mortality caused by a harsh and unpredictable environment is considered to be associated with a fast life history (LH) strategy, commonly linked with criminal behavior. However, offenders are not the only group with a high exposure to extrinsic morbidity-mortality. In the present study, we investigated the LH strategies employed by two groups of Polish men: incarcerated offenders (N = 84) as well as soldiers and firefighters (N = 117), whose professions involve an elevated risk of injury and premature death. The subjects were asked to complete the Mini-K (used as a psychosocial LH indicator) and a questionnaire which included a number of biodemographic LH variables. Although biodemographic and psychosocial LH indicators should be closely linked with each other, the actual connection between them is unclear. Thus, this study was driven by two aims: comparing LH strategies in two groups of men with a high risk of premature morbidity-mortality and investigating the relationship between the biodemographic and psychosocial LH dimensions. The study showed that incarcerated men employed faster LH strategies than soldiers and firefighters, but only in relation to biodemographic variables (e.g., number of siblings, age of sexual initiation, life expectancy). No intergroup differences emerged regarding psychosocial LH indicators. Moreover, the correlation analysis showed a weak association between biodemographic and psychosocial LH indicators. The results strengthen the legitimacy of incorporating biodemographic LH traits into research models and indicate the need for further research on the accuracy of the Mini-K. The possible explanations for the intergroup differences in LH strategies are discussed.

Early external-environmental and internal-health predictors of risky sexual and aggressive behavior in adolescence: An integrative approach

External predictive adaptive response (PAR) models assume that developmental exposures to stress carry predictive information about the future state of the environment, and that development of a faster life history (LH) strategy in this context functions to match the individual to this expected harsh state. More recently internal PAR models have proposed that early somatic condition (i.e., physical health) critically regulates development of LH strategies to match expected future somatic condition. Here we test the integrative hypothesis that poor physical health mediates the relation between early adversity and faster LH strategies. Data were drawn from a longitudinal study (birth to age 16; N = 1,388) of mostly African American participants with prenatal substance exposure. Results demonstrated that both external environmental conditions early in life (prenatal substance exposure, socioeconomic adversity, caregiver distress/depression, and adverse family functioning) and internal somatic condition during preadolescence (birthweight/gestational age, physical illness) uniquely predicted the development of faster LH strategies in adolescence (as indicated by more risky sexual and aggressive behavior). Consistent with the integrative hypothesis, the effect of caregiver distress/depression on LH strategy was mostly mediated by worse physical health. Discussion highlights the implications of these findings for theory and research on stress, development, and health.

Meta-Analysis of Direct and Indirect Effects of Father Absence on Menarcheal Timing

Despite extensive evidence of the association between father absence and early onset of menarche, whether father absence directly accelerates the onset of menarche or the association is mediated by other negative family psychosocial processes remains unclear. Reliable theories on the basis of which father absence has been investigated also vary. Within the life history (LH) theoretical framework, we conducted a meta-analysis of studies that investigated father absence, menarcheal timing, and various family disturbances that cause stress in children. We tested the hypothesis that father absence exerts a direct effect on menarcheal timing and an indirect effect on menarcheal timing mediated by integrated childhood stress. Quantitative synthesis using a two-stage meta-analytic structural equation modeling approach was applied to test our hypothesis. Based on seven research articles (N = 4,619) that include at least one form of family stressor as well as father absence and menarcheal timing, integrated childhood stress emerged as a robust mediator of the association between father absence and early menarcheal timing, and the total effect of father absence on menarcheal timing had reduced in size after accounting for the mediating effect of childhood stress. The findings emphasize the importance of a father figure in regulating a child's LH, including menarcheal timing.

Environmental adversity is associated with lower investment in collective actions

Environmental adversity is associated with a wide range of biological outcomes and behaviors that seem to fulfill a need to favor immediate over long-term benefits. Adversity is also associated with decreased investment in cooperation, which is defined as a long-term strategy. Beyond establishing the correlation between adversity and cooperation, the channel through which this relationship arises remains unclear. We propose that this relationship is mediated by a present bias at the psychological level, which is embodied in the reproduction-maintenance trade-off at the biological level. We report two pre-registered studies applying structural equation models to test this relationship on large-scale datasets (the European Values Study and the World Values Survey). The present study replicates existing research linking adverse environments (both in childhood and in adulthood) with decreased investment in adult cooperation and finds that this association is indeed mediated by variations in individuals’ reproduction-maintenance trade-off.

Confirmatory composite analysis using partial least squares: setting the record straight

Confirmatory composite analysis (CCA) is a subtype of structural equation modeling that assesses composite models. Composite models consist of a set of interrelated emergent variables, i.e., constructs which emerge as linear combinations of other variables. Only recently, Hair et al. (J Bus Res 109(1):101–110, 2020) proposed ‘confirmatory composite analysis’ as a method of confirming measurement quality (MCMQ) in partial least squares structural equation modeling. As a response to their study and to prevent researchers from confusing the two, this article explains what CCA and MCMQ are, what steps they entail and what differences they have. Moreover, to demonstrate their efficacy, a scenario analysis was conducted. The results of this analysis imply that to assess composite models, researchers should use CCA, and to assess reflective and causal–formative measurement models, researchers should apply structural equation modeling including confirmatory factor analysis instead of Hair et al.’s MCMQ. Finally, the article offers a set of corrections to the article of Hair et al. (2020) and stresses the importance of ensuring that the applied model assessment criteria are consistent with the specified model.

Hidden talents in harsh environments

Although early-life adversity can undermine healthy development, children growing up in harsh environments may develop intact, or even enhanced, skills for solving problems in high-adversity contexts (i.e., “hidden talents”). Here we situate the hidden talents model within a larger interdisciplinary framework. Summarizing theory and research on hidden talents, we propose that stress-adapted skills represent a form of adaptive intelligence that enables individuals to function within the constraints of harsh, unpredictable environments. We discuss the alignment of the hidden talents model with current knowledge about human brain development following early adversity; examine potential applications of this perspective to multiple sectors concerned with youth from harsh environments, including education, social services, and juvenile justice; and compare the hidden talents model with contemporary developmental resilience models. We conclude that the hidden talents approach offers exciting new directions for research on developmental adaptations to childhood adversity, with translational implications for leveraging stress-adapted skills to more effectively tailor education, jobs, and interventions to fit the needs and potentials of individuals from a diverse range of life circumstances. This approach affords a well-rounded view of people who live with adversity that avoids stigma and communicates a novel, distinctive, and strength-based message.

Cross-cultural evidence does not support universal acceleration of puberty in father-absent households

Father absence in early life has been shown to be associated with accelerated reproductive development in girls. Evolutionary social scientists have proposed several adaptive hypotheses for this finding. Though there is variation in the detail of these hypotheses, they all assume that family environment in early life influences the development of life-history strategy, and, broadly, that early reproductive development is an adaptive response to father absence. Empirical evidence to support these hypotheses, however, has been derived from WEIRD (Western, Educated, Industrialized, Rich and Democratic) populations. Data from a much broader range of human societies are necessary in order to properly test adaptive hypotheses. Here, we review the empirical literature on father absence and puberty in both sexes, focusing on recent studies that have tested this association beyond the WEIRD world. We find that relationships between father absence and age at puberty are more varied in contexts beyond WEIRD societies, and when relationships beyond the father–daughter dyad are considered. This has implications for our understanding of how early-life environment is linked to life-history strategies, and for our understanding of pathways to adult health outcomes, given that early reproductive development may be linked to negative health outcomes in later life

This article is part of the theme issue ‘Developing differences: early-life effects and evolutionary medicine’.

Psychological origins of the Industrial Revolution: More work is needed!

I am grateful to have received so many stimulating commentaries from interested colleagues regarding the psychological origins of the Industrial Revolution and the role of evolutionary theory in understanding historical phenomena. Commentators criticized, extended, and explored the implications of the perspective I presented, and I wholeheartedly agree with many commentaries that more work is needed. In this response, I thus focus on what is needed to further test the psychological origins of the Industrial Revolution. Specifically, I argue, in agreement with many commentators, that we need: (1) better data about standards of living, psychological preferences, and innovation rates (sect. R1); (2) better models to understand the role of resources (and not just mortality) in driving cultural evolution and the multiple aspects of the behavioral constellation of affluence (sect. R2); and (3) better predictions and better statistical instruments to disentangle the possible mechanisms behind the rise of innovativeness (genetic selection, rational choice, and phenotypic plasticity) (sect. R3).

Developmental Adaptation to Stress: An Evolutionary Perspective

The assumption that early stress leads to dysregulation and impairment is widespread in developmental science and informs prevailing models (e.g., toxic stress). An alternative evolutionary–developmental approach, which complements the standard emphasis on dysregulation, proposes that early stress may prompt the development of costly but adaptive strategies that promote survival and reproduction under adverse conditions. In this review, we survey this growing theoretical and empirical literature, highlighting recent developments and outstanding questions. We review concepts of adaptive plasticity and conditional adaptation, introduce the life history framework and the adaptive calibration model, and consider how physiological stress response systems and related neuroendocrine processes may function as plasticity mechanisms. We then address the evolution of individual differences in susceptibility to the environment, which engenders systematic person–environment interactions in the effects of stress on development. Finally, we discuss stress-mediated regulation of pubertal development as a case study of how an evolutionary–developmental approach can foster theoretical integration.

The ecological roots of human susceptibility to social influence: a pre-registered study investigating the impact of early-life adversity

There is considerable variability in the degree to which individuals rely on their peers to make decisions. Although theoretical models predict that environmental risks shift the cost-benefit trade-off associated with social information use, this idea has received little empirical support. Here we aim to test the effect of childhood environmental adversity on humans' susceptibility to follow others' opinion in the context of a standard face evaluation task. Results collected in a pilot study involving 121 adult participants tested online showed that susceptibility to social influence and childhood environmental adversity are positively associated. Computational analyses further confirmed that this effect is not explained by the fact that participants exposed to early adversity produce noisier decisions overall but that they are indeed more likely to follow the group's opinion. To test the robustness of these findings, a pre-registered direct replication using an optimal sample size was run. The results obtained from 262 participants in the pre-registered study did not reveal a significant association between childhood adversity and task performance but the meta-analysis ran on both the pilot and the pre-registered study replicated the initial finding. This work provides experimental evidence for an association between individuals' past ecology and their susceptibility to social influence.

Testing the indirect effects of somatic and parental effort on stress: the roles of worldviews and coping strategies

Life history theory (LHT) is a mid-level theory from evolutionary biology. LHT, adapted to humans, assumes that individuals can be placed along a single continuum of LH strategies referred to as the slow-to-fast LH continuum: faster life history strategists score higher on mating effort and lower on somatic and parental effort. In the present study we examine the hypothesis that worldview and coping strategies are mediators between somatic and parental effort (SPE) and current perceived stress. 226 participants completed a set of instruments: Mini-K, the World Assumptions Scale, Brief COPE, and the Perceived Stress Scale. In order to test the hypotheses about mediators, Structural Equation Modeling (SEM) was used. The results from the current study showed that individuals allocating their own resources to SPE experienced lower current stress, and felt positive about the benevolence and meaningfulness of the world as well as the worthiness of the self. A more complex linkage was also revealed: individuals displaying SPE endorsed stronger beliefs about self-worth, which in turn was associated with a lower tendency to use disengagement coping and which again translated into a lower level of perceived stress. Furthermore, females investing in SPE maintained a higher level of belief in the meaningfulness of the world, which translated into a higher tendency to use external support for coping.

Ageing with a silver-spoon: A meta-analysis of the effect of developmental environment on senescence

What determines variation between individuals in how they senesce, and are environmental conditions experienced during development relevant to late-life performance? We report a meta-analysis of studies of wild populations to determine how the quality of the environment experienced during development affects rates of survival and reproductive senescence. From studies of 14 bird or mammal species, we calculated effect sizes for the interaction between the effects of environmental quality during development and age in predicting survival (N = 18) or reproduction (N = 30) over time in late life. We found no evidence that developmental environment affected rates of survival senescence (βmean = -1.2 × 10-4 ± 0.022SE). However, a better developmental environment was associated with slower rates of reproductive senescence in late life (βmean = 0.062 ± 0.023SE), indicating a small, but significant, "silver-spoon" effect of early-life conditions that persisted through to late life. Our results illustrate how the effects of environmental conditions during development can persist throughout life, and indicate one possible cause of phenotypic plasticity in senescence.

Human susceptibility to social influence and its neural correlates are related to perceived vulnerability to extrinsic morbidity risks

Humans considerably vary in the degree to which they rely on their peers to make decisions. Why? Theoretical models predict that environmental risks shift the cost-benefit trade-off associated with the exploitation of others' behaviours (public information), yet this idea has received little empirical support. Using computational analyses of behaviour and multivariate decoding of electroencephalographic activity, we test the hypothesis that perceived vulnerability to extrinsic morbidity risks impacts susceptibility to social influence, and investigate whether and how this covariation is reflected in the brain. Data collected from 261 participants tested online revealed that perceived vulnerability to extrinsic morbidity risks is positively associated with susceptibility to follow peers' opinion in the context of a standard face evaluation task. We found similar results on 17 participants tested in the laboratory, and showed that the sensitivity of EEG signals to public information correlates with the participants' degree of vulnerability. We further demonstrated that the combination of perceived vulnerability to extrinsic morbidity with decoding sensitivities better predicted social influence scores than each variable taken in isolation. These findings suggest that susceptibility to social influence is partly calibrated by perceived environmental risks, possibly via a tuning of neural mechanisms involved in the processing of public information.

Psychological origins of the Industrial Revolution

Since the Industrial Revolution, human societies have experienced high and sustained rates of economic growth. Recent explanations of this sudden and massive change in economic history have held that modern growth results from an acceleration of innovation. But it is unclear why the rate of innovation drastically accelerated in England in the eighteenth century. An important factor might be the alteration of individual preferences with regard to innovation resulting from the unprecedented living standards of the English during that period, for two reasons. First, recent developments in economic history challenge the standard Malthusian view according to which living standards were stagnant until the Industrial Revolution. Pre-industrial England enjoyed a level of affluence that was unprecedented in history. Second, behavioral sciences have demonstrated that the human brain is designed to respond adaptively to variations in resources in the local environment. In particular, Life History Theory, a branch of evolutionary biology, suggests that a more favorable environment (high resources, low mortality) should trigger the expression of future-oriented preferences. In this paper, I argue that some of these psychological traits - a lower level of time discounting, a higher level of optimism, decreased materialistic orientation, and a higher level of trust in others - are likely to increase the rate of innovation. I review the evidence regarding the impact of affluence on preferences in contemporary as well as past populations, and conclude that the impact of affluence on neurocognitive systems may partly explain the modern acceleration of technological innovations and the associated economic growth.