Framework Of Life History Theory Research Articles

The extinct osteoarthritic lagomorphs (Prolagus sardus) from Sardinia (Italy) reveal further evidence of life history evolution in insular domains

The study of past pathologies by means of quantitative reports is an underexplored approach to deal with the biology and ecology of extinct taxa. In the present study, we assessed the prevalence rate of primary osteoarthritis in a large sample of Prolagus sardus (Mammalia, Lagomorpha) from Medusa Cave (also known as Grotta Dragonara, Sardinia, Italy; Late Pleistocene) to shed light on the evolutionary history of small mammals under isolation regimes. The hip and knee joints of 246 femora were examined grossly, microscopically, and using advanced radiology, recording essential biological features such as age or weight. We noted that 27.7% of skeletally mature sample had degenerative disorder of the joints, with higher frequency in adults (p-value < 0.05), regardless of their body mass (p-value > 0.05). Histologically, affected joints displayed changes in subchondral plate potentially reflecting adaptive modeling. Our analysis revealed ageing (the extended lifespan) as the main driver of this prevalence rate, whereas mechanical factors (caused by a particular lifestyle) were considered of significantly lesser importance. Our results provide additional empirical support to the analytical framework of life history theory from a new perspective, according to which, under low extrinsic mortality regimes, selection should favor slow-strategies (extended lifespan) in small-sized mammals.

Conservatism and religiousness participate in fast life history dynamics via elevated reproductive motivation

Social attitudes like religiousness and conservatism have been rarely examined in a life history framework. However, there are two competing hypotheses regarding the role of religiousness in human life history: in evolutionary psychological research it is thought to indicate slow life history while the behavioral ecological framework highlights its role in faster life history via elevated reproduction output and lower age of first reproduction. We tested these hypotheses for conservatism and religiousness by analyzing their relations with the variables that measure childhood environmental characteristics, mating effort, and reproductive motivation. The research was conducted via an online study on a sample of young adults in Serbia (N = 528). Bivariate correlations showed that religiousness and conservatism are positively related to reproductive motivation and a beneficial childhood environment, with negative correlations with mating effort. Furthermore, the Network Analysis showed that these two social attitudes are related only to enhanced reproductive motivation when analyzed in a multivariate fashion: conservatism was positively related with reasons favoring parenthood and desired number of children while religiousness was positively related to reasons for parenthood, and negatively for reasons against parenthood and pregnancy planning. Both attitudes had above average centrality indices in the life history network. The results are interpreted in a framework of life history theory and behavioral ecology of social attitudes in general.

Extrinsic and Existential Mortality Risk in Reproductive Decision-Making: Examining the Effects of COVID-19 Experience and Climate Change Beliefs.

While the COVID-19 pandemic has presented an immediate risk to human life around the world, climate change poses an arguably greater—although less immediate—threat to our species’ survival. Within the framework of life-history theory (LHT), this pre-registered study investigated whether extrinsic risk (i.e., external factors that pose a risk to an individual’s life, e.g., COVID-19) and existential risk (i.e., risks with outcomes that threaten the existence of humans as a species, e.g., climate change) had similar or different relationships with reproductive decision-making. A UK representative sample of 325 participants between 18 and 35 years of age was asked to indicate their ideal number of children, ideal age to start having children, and whether their desire for a child had recently changed. Participants were asked about their experiences of COVID-19 and given a series of scales with which to assess their beliefs about climate change. In support of LHT, the study found evidence that knowing people who had been hospitalized with or died of COVID-19 was associated with a greater ideal number of children. Conversely, there was no clear evidence of a relationship between climate change beliefs and reproductive decision-making. The repercussions for understanding how we interpret and respond to different forms of mortality risk are discussed.

Life History Theory: Evolutionary mechanisms and gender role on risk-taking behaviors in young adults

Evolutionary psychology considers the human mind to be composed of multiple specific mechanisms with specific adaptive purposes. This evolutionary approach is in line with the domain-specific view of risk-taking behaviors. Based on the theoretical framework of Life History Theory, the present study analyzes the moderating effect of gender and the mediating effect of evolutionary domain-specific risks in young adult Spaniards (432 participants). K-factor, measured through the Mini-K, was used as an indicator of life history strategy (LHS). Evolutionary domain-specific risks were measured through the Evolutionary Domain-Specific Risk Scale and risk-taking behaviors through the Risky Behavior Questionnaire. Results showed an interaction effect between gender and LHS for rule breaking. Evolutionary domain-specific risks had a mediation effect between LHS and risk-taking behaviors, mainly through mate attraction. These results highlight the different effects of LHS on risk-taking behaviors based on gender and the impact of evolutionary mechanisms. It is, therefore, necessary to consider an evolutionary approach on intervention programs aimed at reducing risk-taking behaviors in young adults.

The appropriate response of Spanish Gitanos: short-run orientation beyond current socio-economic status

Humans differ greatly in their tendency to discount future events, but the reasons underlying such inter-individual differences remain poorly understood. The evolutionary framework of Life History Theory predicts that the extent to which individuals discount the future should be influenced by socio-ecological factors such as mortality risk, environmental predictability and resource scarcity. However, little empirical work has been conducted to compare the discounting behavior of human groups facing different socio-ecological conditions. In a lab-in-the-field economic experiment, we compared the delay discounting of a sample of Romani people from Southern Spain (Gitanos) with that of their non-Romani neighbors (i.e., the majority Spanish population). The Romani-Gitano population constitutes the main ethnic minority in all of Europe today and is characterized by lower socio-economic status (SES), lower life expectancy and poorer health than the majority, along with a historical experience of discrimination and persecution. According to Life History Theory, Gitanos will tend to adopt “faster” life history strategies (e.g., earlier marriage and reproduction) as an adaptation to such ecological conditions and, therefore, should discount the future more heavily than the majority. Our results support this prediction, even after controlling for the individuals’ current SES (income and education). Moreover, group-level differences explain a large share of the individual-level differences. Our data suggest that human inter-group discrimination might shape group members’ time preferences through its impact on the environmental harshness and unpredictability conditions they face.

Retrospective time travel in life satisfaction judgment: A life history approach

We are products of past events and experiences, but only a few of them linger in our memory to affect our present lives. The current research examined whether there are individual differences in how far people look back to judge their present life satisfaction using the evolutionary framework of life history theory. The results showed that perceived ecological uncertainty interacts with a key aspect of life history strategy (childhood socioeconomic status; SES) to influence the span of retrospective mental time travel. When asked to list past events that had crossed their minds during life satisfaction judgments, individuals who grew up in low-SES environments mentioned more recent events, whereas individuals who grew up in high-SES environments wrote more distant past events. This difference was found only when the perception of ecological uncertainty was high, but not when it was low. It appears that life history strategy shapes people's retrospective lens during life satisfaction judgments.

The reproductive costs and benefits associated with the Dark Triad traits in women

We examined (N=201) the sexual health costs and benefits of being high on psychopathy, narcissism, and Machiavellianism in women. The Dark Triad traits were associated with more sexual health disorders, more miscarriages, and pain associated with sexual health. However, narcissism was also associated with a smaller, more attractive waist-to-hip ratio and all the Dark Triad traits were associated with a shorter monthly cycle. Results, while tentative, are discussed within a Life History Theory framework.

Relationships between the Dark Triad and Delayed Gratification: An Evolutionary Perspective

The Dark Triad (i.e., psychopathy, narcissism, and Machiavellianism) is a cluster of socially aversive personality traits that account for the “darker” side of human behavior. While traditional views have focused on the maladaptive nature of these traits, recent work in the field of evolutionary psychology suggests these traits may be adaptive in terms of self-serving behavior. The Dark Triad traits may also be a manifestation of a particular life strategy that an individual engages in; one that is characterized by immediate gratification and risk-taking. The present study examined links between the Dark Triad traits and ability to delay gratification in a sample of 364 undergraduate students (136 males). Psychopathy was the most strongly linked to an inability to delay gratification, followed by Machiavellianism and narcissism. Sex also moderated these relationships, such that women who scored high on Machiavellianism were less likely to delay gratification than men; however, these associations were no longer significant when a more conservative Bonferroni correction was applied. Findings are discussed within the evolutionary framework of Life History Theory.

Gender, risk assessment, and political ambition.

In the United States, women have long held the right to vote and can participate fully in the political process, and yet they are underrepresented at all levels of elected office. Worldwide, men's dominance in the realm of politics has also been the norm. To date, scholars have focused on supply-side and demand-side explanations of women's underrepresentation but differences in how men and women assess electoral risk (the risk involved in seeking political office) are not fully explained. To fill this gap, I explore how evolutionary theory offers insights into gendered differences in political ambition and the evaluation of electoral risk. Using the framework of life-history theory, I hypothesize that both cognitive and environmental factors in human evolution, particularly as they relate to sexual selection and social roles, have shaped the psychology of ambition in gendered ways affecting contemporary politics. Cognitive risk-assessment mechanisms evolving in the hominid line came to be expressed differently in females and males, in women and men. These gendered expressions plausibly reflect differentiable environmental pressures in the past and may help explain behaviors in and barriers to women’s electoral political activity in the present. If so, then the success of efforts to increase such activity — or, regressively, to suppress it — may be better understood.

Adapting to the Destitute Situations: Poverty Cues Lead to Short-Term Choice

BackgroundWhy do some people live for the present, whereas others save for the future? The evolutionary framework of life history theory predicts that preference for delay of gratification should be influenced by social economic status (SES). However, here we propose that the decision to choose alternatives in immediate and delayed gratification in poverty environments may have a psychological dimension. Specifically, the perception of environmental poverty cues may induce people alike to favor choices with short-term, likely smaller benefit than choices with long-term, greater benefit.Methodology/Principal FindingsThe present study was conducted to explore how poverty and affluence cues affected individuals' intertemporal choices. In our first two experiments, individuals exposed explicitly (Experiment 1) and implicitly (Experiment 2) to poverty pictures (the poverty cue) were induced to prefer immediate gratification compared with those exposed to affluence pictures (the affluence cue). Furthermore, by the manipulation of temporary perceptions of poverty and affluence status using a lucky draw game; individuals in the poverty state were more impulsive in a manner, which made them pursue immediate gratification in intertemporal choices (Experiment 3). Thus, poverty cues can lead to short-term choices.Conclusions/SignificanceDecision makers chose more frequently the sooner-smaller reward over the later-larger reward as they were exposed to the poverty cue. This indicates that it is that just the feeling of poverty influences intertemporal choice – the actual reality of poverty (restricted resources, etc.) is not necessary to get the effect. Furthermore, our findings emphasize that it is a change of the poverty-affluence status, not a trait change, can influence individual preference in intertemporal choice.

Life History Theory and Social Psychology

Life History Theory and Social Psychology

Parent–offspring conflict theory: An evolutionary framework for understanding conflict within human families.

Decades of research demonstrate that conflict shapes and permeates a broad range of family processes. In the current article, we argue that greater insight, integration of knowledge, and empirical achievement in the study of family conflict can be realized by utilizing a powerful theory from evolutionary biology that is barely known within psychology: parent-offspring conflict theory (POCT). In the current article, we articulate POCT for psychological scientists, extend its scope by connecting it to the broader framework of life history theory, and draw out its implications for understanding conflict within human families. We specifically apply POCT to 2 instances of early mother-offspring interaction (prenatal conflict and weaning conflict); discuss the effects of genetic relatedness on behavioral conflict between parents, children, and their siblings; review the emerging literature on parent-offspring conflict over the choice of mates and spouses; and examine parent-offspring conflict from the perspective of imprinted genes. This review demonstrates the utility of POCT, not only for explaining what is known about conflict within families but also for generating novel hypotheses, suggesting new lines of research, and moving us toward the "big picture" by integrating across biological and psychological domains of knowledge.

Environmental contingency in life history strategies: The influence of mortality and socioeconomic status on reproductive timing.

Why do some people have children early, whereas others delay reproduction? By considering the trade-offs between using one's resources for reproduction versus other tasks, the evolutionary framework of life history theory predicts that reproductive timing should be influenced by mortality and resource scarcity. A series of experiments examined how mortality cues influenced the desire to have children sooner rather than later. The effects of mortality depended critically on whether people grew up in a relatively resource-scarce or resource-plentiful environment. For individuals growing up relatively poor, mortality cues produced a desire to reproduce sooner--to want children now, even at the cost of furthering one's education or career. Conversely, for individuals growing up relatively wealthy, mortality cues produced a desire to delay reproduction--to further one's education or career before starting a family. Overall, mortality cues appear to shift individuals into different life history strategies as a function of childhood socioeconomic status, suggesting important implications for how environmental factors can influence fertility and family size.

The influence of mortality and socioeconomic status on risk and delayed rewards: A life history theory approach.

Why do some people take risks and live for the present, whereas others avoid risks and save for the future? The evolutionary framework of life history theory predicts that preferences for risk and delay in gratification should be influenced by mortality and resource scarcity. A series of experiments examined how mortality cues influenced decisions involving risk preference (e.g., $10 for sure vs. 50% chance of $20) and temporal discounting (e.g., $5 now vs. $10 later). The effect of mortality depended critically on whether people grew up in a relatively resource-scarce or resource-plentiful environment. For individuals who grew up relatively poor, mortality cues led them to value the present and gamble for big immediate rewards. Conversely, for individuals who grew up relatively wealthy, mortality cues led them to value the future and avoid risky gambles. Overall, mortality cues appear to propel individuals toward diverging life history strategies as a function of childhood socioeconomic status, suggesting important implications for how environmental factors influence economic decisions and risky behaviors.

Enamel microstructure in the fossil bovid Myotragus balearicus (Majorca, Spain): Implications for life-history evolution of dwarf mammals in insular ecosystems

The causes underlying the evolution of insular dwarfs and giants are a matter of ongoing debate. Because body size is among the principle life history traits, recent works aim to understand the evolution of insular dwarfs in the framework of life history theory. However, the hypotheses put forward so far are conflicting. Early studies, suggested that dwarfing is a consequence of selection for an increased reproduction associated to an accelerated life history (formerly r-selection). Recent work, however, based on the analysis of bone histology of the fossil insular dwarf bovid Myotragus balearicus (Balearic Islands, Spain), concluded that dwarfing on islands results from a decrease in growth rate associated to a slow life history (formerly K-selection) in response to selective forces peculiar to insular conditions. In the present work, we reconstruct the schedule of certain life history traits by estimating the rate of dental development and eruption times in M. balearicus and, for comparisons, in an extant caprine (Ovis aries). We used histological techniques to calculate crown formation time, daily secretion rate and crown extension rate, in the lower molars. Eruption pattern in M. balearicus was analysed through the radiological images of an ontogenetic series of mandibles. Our results show that dental crowns grew at slower rates and the period of crown formation was more extended in the dwarfed fossil bovid than in other extant caprines, resulting in dental development and eruption time that doubles that of extant bovids of similar body size. This suggests an important delay in life history schedules. Concordant with the delayed dental development, the striking hypsodonty of Myotragus is indicative of an extended lifespan. These results, together with previous findings from long bone histology, provide empirical evidence for a shift towards a slow life history in this insular dwarfed mammal. Density-dependent resource limitation is hypothesized as the main trigger of the life history and body size evolution of Myotragus.

Attachment and Life History Theory: A Rejoinder

Abstract—M. Del Giudice and J. Belsky (this issue) derive several provocative hypotheses from the application of life history theory to attachment, especially concerning the emergence of sex differences in insecurity in middle childhood. This commentary highlights the significant gaps in research knowledge that must be addressed before the merits of their proposals can be evaluated. It also examines the multiple meanings and functions of “attachment” as this term applies to child–parent and adult affectional relationships, and their association. Their ideas certainly deserve further exploration, especially in the broader context of elucidating the life-span implications of early attachment within the framework of life history theory.

I just cannot control myself: The Dark Triad and self-control

Despite the recent flurry of research on the Dark Triad, this work has been atheoretical. In two studies, totaling 358 participants, we attempt to situate the Dark Triad within the larger framework of Life History Theory by correlating them with three measures of self-control. Both psychopathy (Study 1 and Study 2) and Machiavellianism (Study 2 only) were correlated with low self-control, a tendency to discount future consequences, and high rates of attention deficit disorder. Narcissism was not correlated with measures of self-control in either study. Results are consistent with Life History Theory in that these two sets of psychological traits are expected to be part of a fast life strategy.

Family of origin, age at menarche, and reproductive strategies: A test of four evolutionary-developmental models

Four evolutionary-developmental models within a life history theory framework were compared as to their predictions of the influences of family of origin on age at menarche and differences in reproductive strategies. Predictions of paternal investment theory (Draper & Harpending, 1982), psychosocial acceleration theory (Belsky, Steinberg, & Draper, 1991), polygyny indication model (Kanazawa, 2001), and child development theory (Ellis, 2004) were tested by structural equation modelling in an internet study of 439 women between the ages of 18 and 30. Results show that the existence of a father figure has an impact on the age at menarche, which influences the age at first sexual intercourse. The directions of influences confirm the predictions of paternal investment theory (Draper & Harpending, 1982), psychosocial acceleration theory (Belsky et al., 1991), and child development theory (Ellis, 2004), but not the predictions of the polygyny indication model (Kanazawa, 2001). No significant associations could be found between age at menarche and other reproductive strategy markers; this supports one of the central assumptions of child development theory (Ellis, 2004). Instead, it was the age at first sexual intercourse, influenced by the age at menarche, the existence of a father figure, and participant's educational level, that was most critical for the future reproductive strategies.