Slow and Steady Wins the Race: K Positively Predicts Fertility in the USA and Sweden

On the Incongruence between Psychometric and Psychosocial-Biodemographic Measures of Life History

In evolutionary psychology, it is customary to measure life-history via psychometric inventories such as the Arizona Life History Battery (ALHB). The validity of this approach has been questioned: it is argued that these measures are not congruent with biological life history events, such as the number of children, age at first birth, or pubertal timing. However, empirical data to test this critique are lacking. We therefore administered the ALHB to a convenience sample of young adults in Serbia (N = 447). We also collected information on psychosocial-biodemographic life history parameters closely related to biological life history traits: pubertal timing, onset of sexual behavior, short- and long-term mating, number of children, timing of reproduction, parenthood values, and environmental harshness. We found that correlations between these two sets of measures were rare, unsystematic, and mostly low in magnitude. Stable patterns of relations emerged only between the indicators of environmental conditions from both sets of measures. Furthermore, some ALHB indicators were found to be positively related with early fertility, which is incongruent with the conceptual foundation of ALHB. Finally, network analysis and factor analysis within each set of measures revealed different structures and that the hypothesis of unidimensionality, on which the ALHB was founded, cannot be applied to psychosocial-biodemographic life history indicators. Our results support the critique of ALHB as a set of measures lacking validity to capture biodemographic life-history parameters. ALHB measures are indeed relevant for understanding life-history variation, but they cannot be used as a substitute for specific life history characteristics. Our findings are a warning to researchers to use direct measures of biological events in order to measure life-history dynamics.

Faster life history strategy manifests itself by lower age at menarche, higher sexual desire, and earlier reproduction in people with worse health

Factors which indicate lower life expectancy also induce switching to a faster life strategy, that is, a higher investment in current reproduction at the expense of future reproduction and body maintenance. We tested a hypothesis according to which impairment of individual health serves as a signal for switching to a faster life strategy using online-gathered data from 32,911 subjects. Worse health was associated with lower age at menarche and earlier initiation of sexual life in women and higher sexual desire and earlier reproduction in both sexes. Individuals with worse health also exhibited lower sexual activity, lower number of sexual partners, and lower total number of children. These results suggest that impaired health shifts individuals towards a faster life strategy but also has a negative (physiological) effect on behaviours related to sexual life. Signs of a faster life strategy were also found in Rh-negative men in good health, indicating that even just genetic predisposition to worse health could serve as a signal for switching to a faster life strategy. We suggest that improved public health in developed countries and the resulting shift to a slower life strategy could be the ultimate cause of the phenomenon of demographic transition.

Do Criminals Live Faster Than Soldiers and Firefighters? : A Comparison of Biodemographic and Psychosocial Dimensions of Life History Theory

A high risk of morbidity-mortality caused by a harsh and unpredictable environment is considered to be associated with a fast life history (LH) strategy, commonly linked with criminal behavior. However, offenders are not the only group with a high exposure to extrinsic morbidity-mortality. In the present study, we investigated the LH strategies employed by two groups of Polish men: incarcerated offenders (N = 84) as well as soldiers and firefighters (N = 117), whose professions involve an elevated risk of injury and premature death. The subjects were asked to complete the Mini-K (used as a psychosocial LH indicator) and a questionnaire which included a number of biodemographic LH variables. Although biodemographic and psychosocial LH indicators should be closely linked with each other, the actual connection between them is unclear. Thus, this study was driven by two aims: comparing LH strategies in two groups of men with a high risk of premature morbidity-mortality and investigating the relationship between the biodemographic and psychosocial LH dimensions. The study showed that incarcerated men employed faster LH strategies than soldiers and firefighters, but only in relation to biodemographic variables (e.g., number of siblings, age of sexual initiation, life expectancy). No intergroup differences emerged regarding psychosocial LH indicators. Moreover, the correlation analysis showed a weak association between biodemographic and psychosocial LH indicators. The results strengthen the legitimacy of incorporating biodemographic LH traits into research models and indicate the need for further research on the accuracy of the Mini-K. The possible explanations for the intergroup differences in LH strategies are discussed.

Correction and Validation of Time-Critical Behavioral Measurements over the Internet in the Stage Twin Cohort with More Than 7000 Participants

Behavioral data are increasingly collected over the Internet. This is particularly useful when participants’ own computers can be used as they are, without any modification that relies on their technical skills. However, the temporal accuracy in these settings is generally poor, unknown, and varies substantially across different hard- and software components. This makes it dubious to administer time-critical behavioral tests such as implicit association, reaction time, or various forms of temporal judgment/perception and production. Here, we describe the online collection and subsequent data quality control and adjustment of reaction time and time interval production data from 7127 twins sourced from the Swedish Twin Registry. The purposes are to (1) validate the data that are already and will continue to be reported in forthcoming publications (due to their utility, such as the large sample size and the twin design) and to (2) provide examples of how one might engage in post-hoc analyses of such data, and (3) explore how one might control for systematic influences from specific components in the functional chain. These possible influences include the type and version of the operating system, browser, and multimedia plug-in type

Is Narcissism a Slow Life History Strategy Indicator?: The Answer Depends on the LHS Instrument

The dark triad (DT) traits are differentially related to psychometrically assessed life history strategy (LHS), such that psychopathy is strongly associated with a faster LHS, whereas narcissism appears to be, if anything, a slow LHS indicator. However, the research supporting these generalizations has been based largely on undergraduate samples in which LHS has been measured using the Arizona Life History Battery (ALHB; or its short version the Mini-K), an instrument that arguably lacks adequate coverage of low-extroversion content linked to a slower LHS. In this study, 929 U.S. MTurk workers completed a set of DT instruments, a 10-item Big Five Inventory, a 42-item version of the ALHB (K-SF-42), and the life history rating form (LHRF), which is less weighted toward high extroversion content than the ALHB. Factor analysis of the DT instruments yielded factors corresponding to callousness, secondary psychopathy, and socially adaptive narcissism (leadership/authority and grandiose exhibitionism). Callousness and secondary psychopathy were fast LHS indicators with respect to both LHS instruments. Socially adaptive narcissism appeared as a slow LHS indicator with respect to the K-SF-42 but as a fast LHS indicator with respect to the LHRF. Variation in extroversion accounted entirely for the K-SF-42's positive association with socially adaptive narcissism. This study suggests that narcissism's apparent status as a slow LHS indicator may be more a matter of measurement than of substance.

Slowing life history (K) can account for increasing micro-innovation rates and GDP growth, but not macro-innovation rates, which declined following the end of the Industrial Revolution

Baumard proposes that life history slowing in populations over time is the principal driver of innovation rates. We show that this is only true of micro-innovation rates, which reflect cognitive and economic specialization as an adaptation to high population density, and not macro-innovation rates, which relate more to a population's level of general intelligence.

A Life History Approach to the Female Sexual Orientation Spectrum: Evolution, Development, Causal Mechanisms, and Health

Women's capacity for sexual fluidity is at least as interesting a phenomenon from the point of view of evolutionary biology and behavioral endocrinology as exclusively homosexual orientation. Evolutionary hypotheses for female nonheterosexuality have failed to fully account for the existence of these different categories of nonheterosexual women, while also overlooking broader data on the causal mechanisms, physiology, ontogeny, and phylogeny of female nonheterosexuality. We review the evolutionary-developmental origins of various phenotypes in the female sexual orientation spectrum using the synergistic approach of Tinbergen's four questions. We also present femme-specific and butch-specific hypotheses at proximate and ultimate levels of analysis. This review article indicates that various nonheterosexual female phenotypes emerge from and contribute to hormonally mediated fast life history strategies. Life history theory provides a biobehavioral explanatory framework for nonheterosexual women's masculinized body morphology, psychological dispositions, and their elevated likelihood of experiencing violence, substance use, obesity, teenage pregnancy, and lower general health. This pattern of life outcomes can create a feedback loop of environmental unpredictability and harshness which destabilizes intrauterine hormonal conditions in mothers, leading to a greater likelihood of fast life history strategies, global health problems, and nonheterosexual preferences in female offspring. We further explore the potential of female nonheterosexuality to function as an alloparental buffer that enables masculinizing alleles to execute their characteristic fast life history strategies as they appear in the female and the male phenotype. Synthesizing life history theory with the female sexual orientation spectrum enriches existing scientific knowledge on the evolutionary-developmental mechanisms of human sex differences.

Are Expectations the Missing Link between Life History Strategies and Psychopathology?

Despite advances in knowledge and thinking about using life history theory to explain psychopathology there is still a missing link. That is, we all have a life history strategy, but not all of us develop mental health problems. We propose that the missing link is expectations - a mismatch between expected environmental conditions (including social) set by variations in life history strategies and the current environmental conditions. The mismatch hypothesis has been applied at the biological level in terms of health and disease and we believe that it can also be applied more broadly at the psychological level in terms of perceived expectations in the social environment and the resulting distress-psychopathology-that manifests when our expectations are not met.