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

Abstract

There is considerable variation in health and reproductive behaviours within and across human populations. Drawing on principles from Life History Theory, psychosocial acceleration theory predicts that individuals developing in harsh environments decrease their level of somatic investment and accelerate their reproductive schedule. Although there is consistent empirical support for this general prediction, most studies have focused on a few isolated life history traits and few have investigated the way in which individuals apply life strategies across reproductive and somatic domains to produce coordinated behavioural responses to their environment. In our study, we thus investigate the impact of childhood environmental harshness on both reproductive strategies and somatic investment by applying structural equation modeling (SEM) to cross-sectional survey data obtained in a representative sample of the French population (n = 1015, age: 19-87 years old, both genders). This data allowed us to demonstrate that (i) inter-individual variation in somatic investment (e.g. effort in looking after health) and reproductive timing (e.g. age at first birth) can be captured by a latent fast-slow continuum, and (ii) faster strategies along this continuum are predicted by higher childhood harshness. Overall, our results support the existence of a fast-slow continuum and highlight the relevance of the life history approach for understanding variations in reproductive and health related behaviours.

Environmental harshness is associated with lower investment in collective actions

“…(1) Current harshness - involving poorer reported health and higher number of children. Hence, the latent life-history construct is consistent with prior studies Mell et al, 2018).…”

“…First, current environmental harshness was replaced by childhood environmental harshness, modeled as a composite variable. Composite variables need to be scaled for identification purposes by fixing the coefficient of one of the causal indicators (Mell et al, 2018). Childhood environmental harshness was scaled by setting the path from "parental education" to 1.…”

“…The reason for this is that, all else being equal, the sooner you have children, the more children you can have. This correlation is not captured by the latent variable life-history strategy and is therefore included separately; these two variables indeed covary mechanically (Mell et al, 2018). This resulted in the structural equation model that is presented in figure 3.…”

“…Indeed, greater resource scarcity correlates with virtually all forms of morbidity and mortality, indicating that people who experienced scarcity also experienced greater exposure to disease, disability and death (Adler et al, 1993;Chen et al, 2002;Chetty et al, 2016). In line with this idea, correlational research in humans has shown that early childhood environmental harshness is associated with decreased investment in health and an accelerated reproductive schedule Mell et al, 2018;Nettle, 2011). Causal experiments in non-human animals have also demonstrated that experiencing harshness during the juvenile period has an impact on somatic and reproductive strategies (Reznick & Endler, 1982;Veenema, 2009) and natural experiments in humans have confirmed the causal influence of growing conditions on adult outcomes (Akee et al, 2018).…”

Aggression and risk‐taking as adaptive implementations of fast life history strategy

“…Childhood extrinsic risks and unpredictability have been represented by an array of microenvironmental proxies. These include harsh parenting (Mell, Safra, Algan, Baumard, & Chevallier, 2018) and parental absence (Belsky et al, 1991), employment and residential changes, including homelessness (Doom, Vanzomeren-Dohm, & Simpson, 2016;Masten et al, 2014;Zuo, Huang, Cai, & Wang, 2018), exposure to gangs, violence, and crime Upchurch, Aneshensel, Sucoff, & Levy-Storms, 1999), and low socioeconomic status (SES) (Belsky, Schlomer, & Ellis, 2012), which being associated in many urban areas with drug use, crime, and dangerous neighborhoods represents unsafe more than resource shortages (Chang & Lu, 2018). Both directly and indirectly through child perceived stress (Belsky et al, 1991;Del Giudice, Ellis, & Shirtcliff, 2011), these indicators of early environmental unsafety have been associated with fast LH characteristics including early menarche (Belsky et al, 1991), early initiation of sex (Simpson, Griskevicius, Kuo, Sung, & Collins, 2012) and higher frequency of sexual activity (Baumer & South, 2001), risky substance use behavior , and aggressive, antisocial, and externalizing behaviors Doom et al, 2016;Simpson et al, 2012;Zuo et al, 2018).…”