Birth Weight and Social Trust in Adulthood: Evidence for Early Calibration of Social Cognition

Preference for depth versus breadth in social relationships: Childhood socioeconomic background matters

Although the need for social connection is fundamental, people approach this need through different strategies. Drawing from life history theory, the current research explored whether individuals' early-life experiences are associated with narrow/deep (depth), or broad/shallow (breadth) approach to social relationships. Three studies revealed that participants' childhood socioeconomic status (SES) interacts with perception of economic instability to create diverging preferences in social relationship pattern. Specifically, when economic instability was salient (chronic belief, Study 1; experimentally primed, Studies 2 and 3), individuals from lower-SES childhood preferred a narrower and deeper social network, whereas those from higher-SES childhood preferred a broader and shallower network. Taken together, the present research offers a novel understanding of depth- versus breadth-focused approach to social relationships from the perspective of life history theory.

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.

Pursuing Safety in Social Connection: A Flexibly Fluid Perspective on Risk Regulation in Relationships

People are fundamentally motivated to be included in social connections that feel safe, connections where they are consistently cared for and protected, not hurt or exploited. Romantic relationships have long played a crucial role in satisfying this fundamental need. This article reconceptualizes the risk-regulation model to argue that people draw on experiences from inside and outside their romantic relationships to satisfy their fundamental need to feel safe depending on others. We first review the direct relational cues (i.e., a partner's affectionate touch, responsive versus unresponsive behavior, and relative power) and indirect cues (i.e., bodily sensations, collective value in the eyes of others, and living conditions) that signal the current safety of social connection and motivate people to connect to others or protect themselves against them. We then review how people's chronic capacity to trust in others controls their sensitivity and reactivity to the safety cues. The article concludes with future research directions.

Quantifying the scientific revolution

The Scientific Revolution represents a turning point in the history of humanity. Yet it remains ill-understood, partly because of a lack of quantification. Here, we leverage large datasets of individual biographies (N = 22,943) and present the first estimates of scientific production during the late medieval and early modern period (1300-1850). Our data reveal striking differences across countries, with England and the United Provinces being much more creative than other countries, suggesting that economic development has been key in generating the Scientific Revolution. In line with recent results in behavioural sciences, we show that scientific creativity and economic development are associated with other kinds of creative activities in philosophy, literature, music and the arts, as well as with inclusive institutions and ascetic religiosity, suggesting a common underlying mindset associated with long-term orientation and exploration. Finally, we investigate the interplay between economic development and cultural transmission (the so-called 'Republic of Letters') using partially observed Markov models imported from population biology. Surprisingly, the role of horizontal transmission (from one country to another) seems to have been marginal. Beyond the case of science, our results suggest that economic development is an important factor in the evolution of aspects of human culture.

Moral disciplining: The cognitive and evolutionary foundations of puritanical morality

Why do many societies moralize apparently harmless pleasures, such as lust, gluttony, alcohol, drugs, and even music and dance? Why do they erect temperance, asceticism, sobriety, modesty, and piety as cardinal moral virtues? According to existing theories, this puritanical morality cannot be reduced to concerns for harm and fairness: It must emerge from cognitive systems that did not evolve for cooperation (e.g., disgust-based "purity" concerns). Here, we argue that, despite appearances, puritanical morality is no exception to the cooperative function of moral cognition. It emerges in response to a key feature of cooperation, namely that cooperation is (ultimately) a long-term strategy, requiring (proximately) the self-control of appetites for immediate gratification. Puritanical moralizations condemn behaviors which, although inherently harmless, are perceived as indirectly facilitating uncooperative behaviors, by impairing the self-control required to refrain from cheating. Drinking, drugs, immodest clothing, and unruly music and dance are condemned as stimulating short-term impulses, thus facilitating uncooperative behaviors (e.g., violence, adultery, free-riding). Overindulgence in harmless bodily pleasures (e.g., masturbation, gluttony) is perceived as making people slave to their urges, thus altering abilities to resist future antisocial temptations. Daily self-discipline, ascetic temperance, and pious ritual observance are perceived as cultivating the self-control required to honor prosocial obligations. We review psychological, historical, and ethnographic evidence supporting this account. We use this theory to explain the fall of puritanism in western, educated, industrialized, rich, and democratic (WEIRD) societies, and discuss the cultural evolution of puritanical norms. Explaining puritanical norms does not require adding mechanisms unrelated to cooperation in our models of the moral mind.

Temporal discounting mediates the relationship between socio-economic status and social trust

Social trust and income are associated both within and across countries, such that higher income typically correlates with increased trust. While this correlation is well-documented, the psychological mechanisms sustaining this relationship remain poorly understood. One plausible candidate is people's temporal discounting: on the one hand, trust has a strong time component-it exposes the individual to immediate costs in exchange of uncertain and delayed benefits; on the other hand, temporal discounting is robustly influenced by income. The goal of our studies was to test whether temporal discounting mediates the relationship between income and trust and whether experimentally manipulating perceived income has a downstream impact on temporal discounting and trust. To do so, participants who underestimated their relative income position received information about their true position in the income distribution in order to correct their misperception. Our results indicate that temporal discounting partially mediates the effect of income on social trust in a pre-registered online study on British participants (N = 855). However, receiving a positive information shock on one's income position had no impact on either temporal discounting or social trust. In a second pre-registered study, we replicated the finding that temporal discounting partially mediates the effect of income on social trust in a representative sample of the British population (N = 1130).

Psychometric evaluation of the short form of the Arizona Life History Battery (K-SF-42): A revised Chinese version for emerging adults

Life history (LH) strategies explain how organisms adapt to the environment and make the best use of their resources to fulfill bodily maintenance, growth, reproduction and other functions. The K-SF-42 is a short version of the 199-item Arizona Life History Battery for assessing seven different domains of LH strategies. This article aims to evaluate the psychometric properties of a Chinese version of the K-SF-42. We recruited 1,016 Chinese university students, who aged 16 to 28 years old (M age = 19.47, SD = 1.17) to participant in an anonymous questionnaire. Results of the confirmatory factor analysis supported the second-order six-factor model (except romantic partner attachment), and the scale and subscales of such measurement displayed good internal consistencies. With the exception of religiosity, all of the subscales showed significant positive correlations with a brief unidimensional measure of LH strategies (i.e., the Mini-K). The criterion-related validity of the scale was further supported by the association between its higher score (suggesting slower LH strategies) and the lower levels of childhood harshness and unpredictability. This study provided evidence for the satisfactory applicability of the Chinese version of the K-SF-42 to a Chinese population and contributed to the further investigation of the LH strategies' mechanisms underlying human behavior across cultures.

Tracking historical changes in trustworthiness using machine learning analyses of facial cues in paintings

Social trust is linked to a host of positive societal outcomes, including improved economic performance, lower crime rates and more inclusive institutions. Yet, the origins of trust remain elusive, partly because social trust is difficult to document in time. Building on recent advances in social cognition, we design an algorithm to automatically estimate ratings of perceived trustworthiness evaluations from specific facial cues (such as muscle contractions associated with smiling) detected in European portraits in large historical databases. We used this measure as a proxy of social trust in history. Our results show that estimated levels of perceived trustworthiness in portraits increased over the period 1500–2000. Further analyses suggest that this rise of perceived trustworthiness is associated with increased living standards.

Quantifying how social trust evolved throughout history can help us understand the long-run dynamics of our societies. Here, the authors show an increase in displays of trustworthiness, using a face processing algorithm on early to modern European portraits.

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.

Social motivation is associated with increased weight granted to cooperation-related impressions in face evaluation tasks

It is a trope in psychological science to define the human species as inherently social. Yet, despite its key role in human behaviour, the mechanisms by which social bonding actually shapes social behaviour have not been fully characterized. Across six studies, we show that the motivation for social bonding does not indiscriminately increase individuals’ willingness to approach others but that it is instead associated with specific variations in social evaluations. Studies 1–4 demonstrate that social motivation is associated with a larger importance granted to cooperation-related impressions, i.e. perceived trustworthiness, during social evaluations. Studies 5 and 6 further reveal that this weighting difference leads strongly socially motivated participants to approach more partners that are perceived as both dominant and trustworthy. Taken together, our results provide support for the idea that humans’ social motivation is associated with specific social preferences that could favour successful cooperative interactions and a widening of people’s cooperative circle.

External environment and internal state in relation to life-history behavioural profiles of adolescents in nine countries

The external environment has traditionally been considered as the primary driver of animal life history (LH). Recent research suggests that animals' internal state is also involved, especially in forming LH behavioural phenotypes. The present study investigated how these two factors interact in formulating LH in humans. Based on a longitudinal sample of 1223 adolescents in nine countries, the results show that harsh and unpredictable environments and adverse internal states in childhood are each uniquely associated with fast LH behavioural profiles consisting of aggression, impulsivity, and risk-taking in adolescence. The external environment and internal state each strengthened the LH association of the other, but overall the external environment was more predictive of LH than was the internal state. These findings suggest that individuals rely on a multitude and consistency of sensory information in more decisively calibrating LH and behavioural strategies.

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.

Echoes of Early Life: Recent Insights From Mathematical Modeling

In the last decades, developmental origins of health and disease (DOHaD) has emerged as a central framework for studying early‐life effects, that is, the impact of fetal and early postnatal experience on adult functioning. Apace with empirical progress, theoreticians have built mathematical models that provide novel insights for DOHaD. This article focuses on three of these insights, which show the power of environmental noise (i.e., imperfect indicators of current and future conditions) in shaping development. Such noise can produce: (a) detrimental outcomes even in ontogenetically stable environments, (b) individual differences in sensitive periods, and (c) early‐life effects tailored to predicted future somatic states. We argue that these insights extend DOHaD and offer new research directions.

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.

Religious People Are Trusted Because They Are Viewed as Slow Life-History Strategists

Religious people are more trusted than nonreligious people. Although most theorists attribute these perceptions to the beliefs of religious targets, religious individuals also differ in behavioral ways that might cue trust. We examined whether perceivers might trust religious targets more because they heuristically associate religion with slow life-history strategies. In three experiments, we found that religious targets are viewed as slow life-history strategists and that these findings are not the result of a universally positive halo effect; that the effect of target religion on trust is significantly mediated by the target's life-history traits (i.e., perceived reproductive strategy); and that when perceivers have direct information about a target's reproductive strategy, their ratings of trust are driven primarily by his or her reproductive strategy, rather than religion. These effects operate over and above targets' belief in moralizing gods and offer a novel theoretical perspective on religion and trust.

CLASH's life history foundations

We recommend extending CLASH by incorporating two evolutionary accounts of the shift toward fast life histories under harsh, unpredictable conditions. These accounts, if integrated with CLASH, make different predictions about the distributions of aggression and violence within and between societies. We discuss these predictions and propose ways of testing them.

What is seen and what is not seen in the economy: An effect of our evolved psychology

Specific features of our evolved cognitive architecture explain why some aspects of the economy are "seen" and others are "not seen." Drawing from the commentaries of economists, psychologists, and other social scientists on our original proposal, we propose a more precise model of the acquisition and spread of folk-beliefs about the economy. In particular, we try to provide a clearer delimitation of the field of folk-economic beliefs (sect. R2) and to dispel possible misunderstandings of the role of variation in evolutionary psychology (sect. R3). We also comment on the difficulty of explaining folk-economic beliefs in terms of domain-general processes or biases (sect. R4), as developmental studies show how encounters with specific environments calibrate domain-specific systems (sect. R5). We offer a more detailed description of the connections between economic beliefs and political psychology (sect. R6) and of the probable causes of individual variation in that domain (sect. R7). Taken together, these arguments point to a better integration or consilience between economics and human evolution (sect. R8).

Gender and social mobility modify the effect of birth weight on total and central obesity

BACKGROUND

Little is known about the interaction between gender and low birth weight (LBW) and lifelong social mobility as an explanation of the etiology of obesity. The aim of the present study was to evaluate total and central obesity according to gender, LBW and social mobility, within the context of the epidemiological transition in middle-income countries. We hypothesize that there are more pronounced metabolic consequences of social mobility for women born with LBW.

METHODS

We used data from a birth cohort study conducted in Ribeirão Preto, São Paulo, Brazil. Data regarding anthropometric measurements, schooling and smoking status were collected at 23-25 years of age. Social mobility was determined based on maternal and adult offspring schooling and categorized as Low-Low, Low-High and High-High. Analysis of covariance was performed to assess the association between social mobility and body mass index (BMI) or waist circumference (WC) in adulthood, stratified by LBW and gender.

RESULTS

Data on 6827 singleton pregnancies were collected at birth in 1978/79 and a sample was followed up in 2002/04. A total of 2063 subjects were included in the study. Mean age was 23.9 ± 0.7 years, 51.8% (n = 1068) were female and the LBW was 6.2% (n = 128). There was a triple interaction between social mobility, LBW and gender. Among women born without LBW, BMI and WC were higher in the Low-Low group compared to High-High schooling group. Among LBW women, BMI and WC were higher in the Low-Low group compared to the Low-High group.

CONCLUSIONS

Women born with LBW belonging to the low schooling group in early adulthood had high BMI and WC, compared to the Low-High social mobility group.

Human Life History Strategies

Human life history (LH) strategies are theoretically regulated by developmental exposure to environmental cues that ancestrally predicted LH-relevant world states (e.g., risk of morbidity-mortality). Recent modeling work has raised the question of whether the association of childhood family factors with adult LH variation arises via (i) direct sampling of external environmental cues during development and/or (ii) calibration of LH strategies to internal somatic condition (i.e., health), which itself reflects exposure to variably favorable environments. The present research tested between these possibilities through three online surveys involving a total of over 26,000 participants. Participants completed questionnaires assessing components of self-reported environmental harshness (i.e., socioeconomic status, family neglect, and neighborhood crime), health status, and various LH-related psychological and behavioral phenotypes (e.g., mating strategies, paranoia, and anxiety), modeled as a unidimensional latent variable. Structural equation models suggested that exposure to harsh ecologies had direct effects on latent LH strategy as well as indirect effects on latent LH strategy mediated via health status. These findings suggest that human LH strategies may be calibrated to both external and internal cues and that such calibrational effects manifest in a wide range of psychological and behavioral phenotypes.

Distrust As a Disease Avoidance Strategy: Individual Differences in Disgust Sensitivity Regulate Generalized Social Trust

Throughout human evolutionary history, cooperative contact with others has been fundamental for human survival. At the same time, social contact has been a source of threats. In this article, we focus on one particular viable threat, communicable disease, and investigate how motivations to avoid pathogens influence people's propensity to interact and cooperate with others, as measured by individual differences in generalized social trust. While extant studies on pathogen avoidance have argued that such motivations should prompt people to avoid interactions with outgroups specifically, we argue that these motivations should prompt people to avoid others more broadly. Empirically, we utilize two convenience samples and a large nationally representative sample of US citizens to demonstrate the existence of a robust and replicable effect of individual differences in pathogen disgust sensitivity on generalized social trust. We furthermore compare the effects of pathogen disgust sensitivity on generalized social trust and outgroup prejudice and explore whether generalized social trust to some extent constitutes a pathway between pathogen avoidance motivations and prejudice.