Early stress, parental motivation, and reproductive decision-making: applications of life history theory to parental behavior

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.

Family support during childhood as a predictor of mate retention and kin care in adults during the COVID-19 pandemic in Brazil: an exploratory study

Introduction

Experiences during development help to explain behavior expression in adulthood.

Aims

In this study, we explored how unpredictability and harshness experienced during childhood may have impacted the occurrence of reproductive milestones in adulthood and the expression of fundamental motives related to self-protection, disease avoidance, mate seeking, mate retention, and kin care (children/family) during the pandemic.

Methods

This was an exploratory study with 438 participants. Through the administration of online questionnaires, participants were assessed and categorized based on their childhood experiences, resulting in three groups: low unpredictability, high unpredictability with family support, and high unpredictability without family support.

Results

We found that family support experienced during childhood predicts a slow life-history strategy. This involves an emphasis on growth and parenting efforts at the expense reproduction and was relevant even for participants who faced financial unpredictability. During the pandemic, we also observed that mate retention and kin care (family) motives were predominant among individuals who had greater family support during childhood.

Discussion

Overall, the findings suggest that unpredictability experienced during childhood is crucial for the development of life-history strategies and the manifestation of fundamental motives in adulthood.

Earlier sexual debut predicts higher (not lower) levels of father care measured across 12 weeks: an experience sampling study

Across the lifespan, males negotiate the tradeoff between current and future reproduction. From a life history theory (LHT) perspective, resources invested into earlier reproduction pose a cost to later reproduction. The age of sexual debut is a commonplace measure of sexual maturation. However, in males, thorarche (age of first ejaculation) and years from thorarche to age of first reproduction both represent milestones related to reproductive timing. A fundamental prediction from LHT is that earlier sexual maturation-a "quantity" strategy-predicts decreased levels of care per offspring. In the current study, we test this straightforward relationship looking specifically at a father's investment of time. In a sample of first-time fathers, we measured the amount of time spent with their 9-to-12-month infants longitudinally using an experience sampling method (ESM)-an ecologically valid method of collecting self-report data on fathers' use of time Fathers contributed data on their time allocation across a 12-week period. They reported on ages of sexual debut, thorarche, and the years between thorarche and first reproduction (i.e., current age) was calculated. Only age of sexual debut had a relationship with time allocated toward infants. Importantly however, this effect was in a direction opposite of our LHT derived hypothesis. Males with earlier sexual debut spent more time with their infants. Discussion focuses on the potential contributions to this finding and limitations related to small effect size, methods and measurement, and sample demographics.

Neither environmental unpredictability nor harshness predict reliance on alloparental care among families in Cebu, Philippines

Alloparental caregiving is key to humans' highly flexible reproductive strategies. Across species and across societies, alloparental care is more common in harsh and/or unpredictable environments (HUEs). Currently, however, it is unclear whether HUEs predict intra-population variation in alloparental care, or whether early life HUEs might predict later alloparental care use in adulthood, consistent with adaptive developmental plasticity. We test whether harshness measures (socioeconomic status (SES), environmental hygiene, crowding) and unpredictability measures (parental unemployment, paternal absence, household moves) predicted how much alloparental assistance families in Cebu, Philippines received, in a multigenerational study with data collected across four decades. Though worse environmental hygiene predicted more concurrent alloparental care in 1994, we found little evidence that HUEs predict within-population variation in alloparental care in this large-scale, industrialized society. Indeed, less-crowded conditions and higher SES predicted more alloparental care, not less, in the 1980s and in 2014 respectively, while paternal absence in middle childhood predicted less reliance on alloparental care in adulthood. In this cultural context, our results generally do not provide support for the translation of interspecific or intersocietal patterns linking HUEs and alloparental care to intra-population variation in alloparental care, nor for the idea that a reproductive strategy emphasizing alloparental care use may be preceded by early life HUEs.

Time Wasters?

Abstract. The Dark Triad personality traits have previously been linked with dysfunctional types of procrastination (i.e., delaying certain tasks). From an evolutionary perspective, procrastination is recognized for facilitating a fast life history strategy. The present study investigated links between active and passive procrastination and the extended Dark Tetrad personality traits (psychopathy, Machiavellianism, narcissism, sadism). Participants ( N = 357) were invited via Prolific data collection platform and Survey Circle research sites to participate in an online survey exploring personality and procrastination. Path analyses revealed that all Dark Tetrad traits positively predicted several aspects of active procrastination only. Narcissism emerged as the only negative predictor of passive procrastination. Rather than linking these traits with dysfunctional procrastination types only, our results highlight the importance of considering the Dark Tetrad about functional forms of procrastination, which may be more beneficial for facilitating a fast life history strategy.

Gene-environment correlations and causal effects of childhood maltreatment on physical and mental health: a genetically informed approach

BACKGROUND

Childhood maltreatment is associated with poor mental and physical health. However, the mechanisms of gene-environment correlations and the potential causal effects of childhood maltreatment on health are unknown. Using genetics, we aimed to delineate the sources of gene-environment correlation for childhood maltreatment and the causal relationship between childhood maltreatment and health.

METHODS

We did a genome-wide association study meta-analysis of childhood maltreatment using data from the UK Biobank (n=143 473), Psychiatric Genomics Consortium (n=26 290), Avon Longitudinal Study of Parents and Children (n=8346), Adolescent Brain Cognitive Development Study (n=5400), and Generation R (n=1905). We included individuals who had phenotypic and genetic data available. We investigated single nucleotide polymorphism heritability and genetic correlations among different subtypes, operationalisations, and reports of childhood maltreatment. Family-based and population-based polygenic score analyses were done to elucidate gene-environment correlation mechanisms. We used genetic correlation and Mendelian randomisation analyses to identify shared genetics and test causal relationships between childhood maltreatment and mental and physical health conditions.

FINDINGS

Our meta-analysis of genome-wide association studies (N=185 414) identified 14 independent loci associated with childhood maltreatment (13 novel). We identified high genetic overlap (genetic correlations 0·24-1·00) among different maltreatment operationalisations, subtypes, and reporting methods. Within-family analyses provided some support for active and reactive gene-environment correlation but did not show the absence of passive gene-environment correlation. Robust Mendelian randomisation suggested a potential causal role of childhood maltreatment in depression (unidirectional), as well as both schizophrenia and ADHD (bidirectional), but not in physical health conditions (coronary artery disease, type 2 diabetes) or inflammation (C-reactive protein concentration).

INTERPRETATION

Childhood maltreatment has a heritable component, with substantial genetic correlations among different operationalisations, subtypes, and retrospective and prospective reports of childhood maltreatment. Family-based analyses point to a role of active and reactive gene-environment correlation, with equivocal support for passive correlation. Mendelian randomisation supports a (primarily bidirectional) causal role of childhood maltreatment on mental health, but not on physical health conditions. Our study identifies research avenues to inform the prevention of childhood maltreatment and its long-term effects.

FUNDING

Wellcome Trust, UK Medical Research Council, Horizon 2020, National Institute of Mental Health, and National Institute for Health Research Biomedical Research Centre.

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.

The relevance of a rodent cohort in the Consortium on Individual Development

One of the features of the Consortium on Individual Development is the existence of a rodent cohort, in parallel with the human cohorts. Here we give an overview of the current status. We first elaborate on the choice of rat and mouse models mimicking early life adverse or beneficial conditions during development. We performed a systematic literature search on early life adversity and adult social behavior to address the status quo. Next, we describe the behavioral tasks we used and designed to examine behavioral control and social competence in rodents. The results so far indicate that manipulation of the environment in the first postnatal week only subtly affects social behavior. Stronger effects were seen in the model that targeted early adolescence; once adult, these rats are characterized by increased attention, a higher degree of impulsiveness and reduced social interest in peers. Many experiments in our rodent models with tightly controlled conditions were inspired by findings in human cohorts, and now allow in-depth mechanistic investigations. Vice versa, some of the findings in rodents are currently followed up by dedicated investigations in the human cohorts. This exemplifies the added value of animal investigations in a consortium encompassing primarily human developmental cohorts.

Firm parenting and youth adjustment: Stress reactivity and dyadic synchrony of respiratory sinus arrhythmia

Parental behaviors are potent risk and protective factors for youth development of externalizing problems. Firm control is a parenting strategy that is inconsistently linked to youth adjustment, possibly due to variations in individual biological contexts. Growing research shows that dyadic coregulation of the autonomic nervous system (e.g., parent-child physiological synchrony) is a neurobiological mechanism that links parenting to youth adjustment. However, physiological synchrony may be context-dependent (e.g., adaptive in positive interactions, maladaptive in negative interactions). We aimed to test the role of dyadic synchrony in respiratory sinus arrhythmia (RSA) during parent-child conflict as a mediator between parent firm control and youth's externalizing problems. To capture youth's stress reactivity, we also tested how galvanic skin response reactivity (GSR-R) moderated this indirect path. The sample included 101 dyads of low socioeconomic-status at-risk preadolescents and parents. Results indicated that youth higher levels of GSR-R significantly intensified the link between parent firm control and dyadic RSA synchrony during conflict. Dyadic RSA synchrony further predicted youth increased in externalizing problems. Overall, results suggest that when parents employ firm control parenting with highly reactive teens, dyadic RSA synchrony elevates, potentially modeling less optimal coping with conflict for the youth, which is associated with increased externalizing problems.

Synthesizing Views to Understand Sex Differences in Response to Early Life Adversity

Sex as a biological variable (SABV) is critical for understanding the broad range of physiological, neurobiological, and behavioral consequences of early life adversity(ELA). The study of the interaction of SABV and ELA ties into several current debates, including the importance of taking into account SABV in research, differing strategies employed by males and females in response to adversity, and the possible evolutionary and developmental mechanisms of altered development in response to adversity. This review highlights the importance of studying both sexes, of understanding sex differences (and similarities) in response to ELA, and provides a context for the debate surrounding whether the response to ELA may be an adaptive process.

Effortful Control Development in the Face of Harshness and Unpredictability

Using psychosocial acceleration theory, this multimethod, multi-reporter study examines how early adversity adaptively shapes the development of a self-regulation construct: effortful control. Investigation of links between early life harshness and unpredictability and the development of effortful control could facilitate a nuanced understanding of early environmental effects on cognitive and social development. Using the Building Strong Families national longitudinal data set, aspects of early environmental harshness and early environmental unpredictability were tested as unique predictors of effortful control at age 3 using multiple regression. Early harshness variables were financial harshness, mothers' and fathers' observed parenting, mothers' and fathers' reported use of harsh discipline, and harsh neighborhood conditions. Early unpredictability was measured by number of paternal transitions. Cues of harshness, specifically observed unresponsive parenting, observed harsh parenting, and neighborhood harshness, did significantly negatively predict effortful control. Paternal transitions also significantly predicted effortful control, but in the opposite (i.e., positive) direction. The results corroborate previous research linking quality of parenting to the development of children's effortful control and place it within an evolutionary-developmental theoretical framework. Further, the results suggest that neighborhood harshness may also direct developmental trajectories of effortful control in young children, though the mechanisms through which this occurs are still unclear. This is the first study to explicitly investigate effortful control development in early childhood within the harshness and unpredictability framework.

Early Environmental Unpredictability: Implications for Youth's Perceptions and Social Functioning

According to an evolutionary perspective, early environmental unpredictability induces expectations in youth that their future is uncertain and increases their likelihood of engaging in opportunistic, impulsive, and aggressive behaviors. Although considerable evidence supports the links between environmental unpredictability and such behaviors, less is known about how youth growing up in volatile environments actually perceive their lives and how these perceptions relate to their behavior. In this study, two samples of 10-17 year-olds, one with a history of maltreatment and removal from home (n = 90; 52% female; 67% Hispanic-American) and one without (n = 80; 54% female; 69% Hispanic-American), reported on their perceptions of unpredictability and social functioning. Maltreated youth endorsed greater perceptions of unpredictability than non-maltreated youth. For both groups, greater perceptions of unpredictability were associated with increased aggression and conduct problems and decreased prosociality. Findings advance understanding of a developmental pathway contributing to opportunistic and risky social behavior in youth.

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.

Attachment theory grows up: a developmental approach to pair bonds

The application of Bowlby's Attachment Theory (AT) to sexual pair bonds has sparked wide ranging investigations which largely support, and further elaborate, key tenets of AT. Most notably, adults, like children, derive security from, and function optimally, when they feel they have the commitment of a loving other. Recent neuroscience findings further support the premise that parent-child and sexual pair bonds share some of the same neural architecture and physiology. The application of AT to adult pair bonds has also provoked controversy and raised empirical questions that warrant greater attention. Some of these questions include whether platonic friendships or kin can serve at least some of the functions of sexual partnerships in adulthood, and when, in the course of their development, do sexual relationships become pair bonds. Attention to key differences between infant and adult attachment, and the application of a developmental approach to pair bonds, would lead to productive directions for future research.

Parenting and SES: relative values or enduring principles?

The quality of parenting is a complex and multiply determined construct that is strongly influenced by the larger ecological context in which it evolves. A substantial body of literature has documented associations between socioeconomic status (SES) and parenting but has been limited in its consideration of factors that may explain or moderate the nature of this relation. The socioeconomic conditions within which a family lives may powerfully influence parenting through its effects on parental mental health and via differential access to resources. Parents' childrearing knowledge and cultural values may also vary along a socioeconomic gradient, with downstream effects on parenting. Further, both socioeconomic factors and parenting can independently shape children's health and development. A more comprehensive understanding of linkages between SES and parenting may inform preventive intervention efforts to support families from disadvantaged environments.