Life history theory suggests that in risky and uncertain environments the optimal reproductive strategy is to reproduce early in order to maximize the probability of leaving any descendants at all. The fact that early menarche facilitates early reproduction provides an adaptationist rationale for our first two hypotheses: that women who experience more risky and uncertain environments early in life would have (1) earlier menarche and (2) earlier first births than women who experience less stress at an early age. Attachment theory (...) and research provide the rationale for our second two hypotheses: that the subjective early experience of risky and uncertain environments (insecurity) is (3) part of an evolved mechanism for entraining alternative reproductive strategies contingent on environmental risk and uncertainty and (4) reflected in expected lifespan. Evidence from our pilot study of 100 women attending antenatal clinics at a large metropolitan hospital is consistent with all four hypotheses: Women reporting more troubled family relations early in life had earlier menarche, earlier first birth, were more likely to identify with insecure adult attachment styles, and expected shorter lifespans. Multivariate analyses show that early stress directly affected age at menarche and first birth, affected adult attachment in interaction with expected lifespan, but had no effect on expected lifespan, where its original effect was taken over by interactions between age at menarche and adult attachment as well as age at first birth and adult attachment. We discuss our results in terms of the need to combine evolutionary and developmental perspectives and the relation between early stress in general and father absence in particular. (shrink)

In public health emergencies, people are more willing to save money rather than spending it, which is not conductive to economic development and recovery. Due to the absence of relevant research, the internal logic of this phenomenon is not clear. In the context of the COVID-19 pandemic, this study systematically explored whether and why public health emergencies stimulate consumers' preference for saving. We conducted two online surveys and used methods including stepwise regression analysis and bootstrapping to test the hypotheses. The (...) first survey, with 1,511 participants from China in February 2020, indicates that the severity of emergencies has a significant positive impact on the populations' willingness to save. Risk perception plays a mediating role between the severity of emergencies and consumers' saving willingness. Materialism plays a moderating role between risk perception and an individual's saving willingness, individuals who are more materialistic have a lower saving willingness when they perceive the risks of the pandemic. To verify the duration of the above effects, we conducted a follow-up survey consisted of 466 instances in August 2020. It is noteworthy that the above effects are not significant during the post-pandemic period. Thus, spending behavior in public health emergencies can be motived by reducing risk perception and increasing materialism. These findings can provide a valuable inspiration for public health, crisis management, and economic recovery during public health emergencies. (shrink)

Life history theory predicts that greater extrinsic mortality will lead to earlier and higher fertility. To test this prediction, I examine the relationship between life expectancy at birth and several proxies for life history traits (ages at first sex and first marriage, total fertility rate, and ideal number of children), measured for both men and women. Data on sexual behaviors come from the Demographic and Health Surveys (DHS). Two separate samples are analyzed: a cross-sectional sample of 62 countries and a (...) panel sample that includes multiple cross-sectional panels from 48 countries. Multivariate regression analysis is used to control for potential confounding variables. The results provide only partial support for the predictions, with greater support among women than men. However, the prediction is not supported in sub-Saharan African countries, most likely owing to the nonequilibrium conditions observed in sub-Saharan Africa with respect to life expectancy. The applicability of the model to understanding HIV/AIDS risk behaviors is discussed. (shrink)

Parental investment strategies are contingent on parental capacities and ecology. Parental embodied capital may be important in aspiration construction and investments in children’s human capital, which is especially important in urban environments where skills are directly tied to wage income. For Indo-Fijians, rural ecology strongly limits opportunities. Here this limitation is conceptualized as extrinsic risk and immune to reduction through enhanced parental investment. Urban migration is interpreted as a risk reduction strategy, given an expanded urban opportunity structure (lower extrinsic risk). (...) Qualitative and quantitative data from 678 Indo-Fijian children suggest that, contingent on parental capacities, parents migrate in response to their perceptions of decreased opportunities that manifest as high levels of extrinsic risk in rural environments. Parental investment in quality and quantity corresponds to parental perceptions of extrinsic risk, which in turn correspond to migration status, indicating that parental strategies do respond to perceived limits on investment payoffs. (shrink)

During human evolutionary history, there were “trade-offs” between expending time and energy on child-rearing and mating, so both men and women evolved conditional mating strategies guided by cues signaling the circumstances. Many short-term matings might be successful for some men; others might try to find and keep a single mate, investing their effort in rearing her offspring. Recent evidence suggests that men with features signaling genetic benefits to offspring should be preferred by women as short-term mates, but there are trade-offs (...) between a mate's genetic fitness and his willingness to help in child-rearing. It is these circumstances and the cues that signal them that underlie the variation in short- and long-term mating strategies between and within the sexes. Key Words: conditional strategies; evolutionary psychology; fluctuating asymmetry; mating; reproductive strategies; sexual selection. (shrink)

Life history theory aims to explain the relationship between life events, recognizing that the fertility and growth schedules of organisms are dependent on environmental conditions and an organism’s ability to extract resources from its environment. Using models from life history theory, we predict life expectancy to be positively correlated with educational investments and negatively correlated with adolescent reproduction and total fertility rates. Analyses of UN data from 193 countries support these predictions and demonstrate that, although variation is evident across world (...) regions, strong interactions exist among life expectancy, reproductive investments, and educational attainment, and these relationships occur independently of economic pressures and disease burdens. The interactions are strongest, however, in countries with a life expectancy of ≥60 years as these countries tend to have stable economies and a limited HIV/AIDS burden. These findings suggest that policies aimed at influencing education and reproductive decisions should consider environmental characteristics that drive people’s expectations about their longevity. (shrink)

This paper investigates hypotheses drawn from two sources: (1) Belsky, Steinberg, and Draper’s (1991) attachment theory model of the development of reproductive strategies, and (2) recent life history models and comparative data suggesting that environmental risk and uncertainty may be potent determinants of the optimal tradeoff between current and future reproduction. A retrospective, self-report study of 136 American university women aged 19–25 showed that current recollections of early stress (environmental risk and uncertainty) were related to individual differences in adult time (...) preference and adult sexual behavior, and that individual differences in time preference were related to adult attachment organization and sexual behavior. These results are consistent with the hypothesis that perceptions of early stress index environmental risk and uncertainty and mediate the attachment process and the development of reproductive strategies. On this view individual differences in time preference are considered to be part of the attachment theoretical construct of an internal working model, which itself is conceived as an evolved algorithm for the contingent development of alternative reproductive strategies. (shrink)

The aim of this study is an analysis of the possible adaptive consequences of delivery of low birth weight infants. We attempt to reveal the cost and benefit components of bearing small children, estimate the chance of the infants’ survival, and calculate the mothers’ reproductive success. According to life-history theory, under certain circumstances mothers can enhance their lifetime fitness by lowering the rate of investment in an infant and/or enhancing the rate of subsequent births. We assume that living in a (...) risky environment and giving birth to a small infant may involve a shift from qualitative to quantitative production of offspring. Given high infant mortality rates, parents will have a reproductive interest in producing a relatively large number of children with a smaller amount of prenatal investment. This hypothesis was tested among 650 Gypsy and 717 non-Gypsy Hungarian mothers. Our study has revealed that 23.8% of the Gypsy mothers had low birth weight (<2,500 g) children, whose mortality rate is very high. These mothers also had more spontaneous abortions and stillbirths than those with normal weight children. As a possible response to these reproductive failures, they shortened birth spacing, gaining 2–4 years across their reproductive lifespan for having additional children. Because of the relatively short interbirth intervals, by the end of their fertility period, Gypsy mothers with one or two low birth weight infants have significantly more children than their ethnic Hungarian counterparts. They appear to compensate for handicaps associated with low birth weights by having a larger number of closely spaced children following the birth of one or more infants with a reduced probability of survival. The possible alternative explanations are discussed, and the long-term reproductive benefits are estimated for both ethnic groups. (shrink)

This thesis assessed whether rape is an adaptive mating strategy. which was naturally selected for in our ancestral past. It investigated a number of constructs. namely: fertility value; victim-offender relationship; socio-economic status; rape proclivity; actual sexual aggression; and sociosexual orientation. There were two types of studies: studies 1-3 involved archival data, e.g. the use of criminal statistics. and studies 4-7 assessed participant data, e.g. rape attitudes. Study 1 found that fertility value was related to rape prevalence, as was reproductive value. (...) In addition, offenders with a nonreproductive sexual preference tended to rape a victim with a low FV. and offenders who committed a secondary offence tended to rape a victim with high FV. Study 2 found that there was a smaller number of offences committed against strangers and partners, and a larger number committed against step-relatives and acquaintances. More rapes were committed by low status than high status men. even when the base rate was accounted for. Study 3, showed that there was a relationship between the population gender ratio and rape prevalence. However. the covariable population density was positively related to rape prevalence. Study 4- found that there was more disapproval of a depicted rape committed by a low status offender. A low status offender who raped a victim with low RV attracted more disapproval. Study 5 showed that marital rape was disapproved of more than both stranger and acquaintance rape. Individuals with a short-term mating strategy disapproved of rape more than those with a long-term strategy, and a long-term strategist disapproved of a marital rape less than a short-term strategist. Study 6 found that those who possessed a promiscuous ideology perceived their future life to be limited, in particular the likelihood of being happily married. There was no relationship found between perceived future life and sexual aggression. In study 7. it was found that those who had a more unrestricted sociosexual orientation were more likely to have asymmetrical bodily traits. and that the right hand 20:40 digit ratio was significantly related to actual sexual aggression. Overall. there was partial support for rape as an adaptive mechanism. but the studics wcre also consistent with a by-product explanation of rape. (shrink)

Life history theory predicts that exposure to high mortality in early childhood leads to faster and riskier reproductive strategies. Individuals who grew up in a high mortality regime will not overly wait until they find a suitable partner and form a stable union because premature death would prevent them from reproducing. Cox proportional hazard models were used to determine whether women who experienced sibling death during early childhood (0–5 years) reproduced earlier and were at an increased risk of giving birth (...) to an illegitimate child, with illegitimacy serving as a proxy for risky sexual behavior. Furthermore, we investigate whether giving birth out of wedlock is influenced by individual mortality experience or by more promiscuous sexual behavior that is clustered in certain families. Models are fitted on pedigree data from the eighteenth- and nineteenth-century Krummhörn population in Germany. The results show a relationship between sibling death in early childhood and the risk of reproducing out of wedlock, and reproductive timing. The risk of giving birth out of wedlock is linked to individual mortality experience rather than to family-level effects. In contrast, adjustments in connubial reproductive timing are influenced more by family-level effects than by individual mortality experience. (shrink)

Following from life history and attachment theory, individuals are predicted to be sensitive to variation in environmental conditions such that risk and uncertainty are internalized by cognitive, affective, and psychobiological mechanisms. In turn, internalizing of environmental uncertainty is expected to be associated with attitudes toward risk behaviors and investments in education. Native American youth aged 10–19 years (n = 89) from reservation communities participated in a study examining this pathway. Measures included family environmental risk and uncertainty, present and future time (...) perspective, adolescent attachment, attitudes toward risk, investments in education, and salivary cortisol. Results support the idea that environmental risk and uncertainty are internalized during development. In addition, internalizing mechanisms significantly predicted attitudes toward risk and education: (1) lower scores on future time perspective and higher cortisol predicted higher scores on risk attitudes, and (2) higher scores on future time perspective and lower scores on problems with attachment predicted higher self-reported school performance. Gender differences were seen, with males anticipating a shorter lifespan than females, which predicted higher scores on risk attitudes and lower school performance. Implications for research on adolescent problem behavior and academic achievement are discussed. (shrink)