Eating Disorders and Intrasexual Competition: Testing an Evolutionary Hypothesis among Young Women

The sexual competition hypothesis (SCH) contends that intense female intrasexual competition (ISC) is the ultimate cause of eating disorders. The SCH explains the phenomenon of the pursuit of thinness as an adaptation to ISC in the modern environment. It argues that eating disorders are pathological phenomena that arise from the mismatch between the modern environment and the inherited female adaptations for ISC. The present study has two aims. The first is to examine the relationship between disordered eating behavior (DEB) and ISC in a sample of female undergraduates. The second is to establish whether there is any relationship between disordered eating behavior and life history (LH) strategy. Participants completed a battery of questionnaires examining eating-related attitudes and behaviors, ISC, and LH strategy. A group of 206 female undergraduates were recruited. A structural equation model was constructed to analyze the data. ISC for mates was significantly associated with DEB, as predicted by the SCH. DEB was found to be predicted by fast LH strategy, which was only partially mediated by the SCH. The results of this study are supportive of the SCH and justify research on a clinical sample

Body Mass Index, Sleep Quality, Stress Conditions Determine Menstrual Cycles Among Female Adolescents

Menstrual cycles are an important indicator of women's health. Menstrual cycles can be affected by body mass index (BMI), sleep quality, and stress. This study aimed to analyse the relationship between BMI, sleep quality, stress and the menstrual cycle. The subjects of this research were the female adolescents at the age of at least 15 years old that had experienced menstruation for at least 2 years. The dependent variable is the menstrual cycle while the independent variables are BMI, sleep quality, and stress conditions. Observational analytic research method with Cross sectional design was used in this research. The subjects were 148 female students. The BMI data were obtained through the anthropometric measurement. The sleep quality data were taken with PSQI questionnaire, and the stress condition data obtained from PSS-10 questionnaire which were then analysed using Chi-Square test and Logistic Regression. Results of study showed that there is a significant relationship between BMI, sleep quality, stress conditions and the adolescent menstrual cycle. The results of the multivariate analysis showed that the female adolescents with abnormal BMI are at risk of having menstrual cycle disorders 1.91 times. The adolescents with poor sleep quality are at risk experiencing menstrual cycle disorders 2.05 times, and the adolescents with stress conditions at risk of the menstrual cycle disorders 2.26 times. There is a relationship between BMI, sleep quality, stress conditions and the menstrual cycle. Stress conditions most influence the regularity of the menstrual cycle

Life History Strategies and Individual Variation in Men's Desire to Appear Muscular.

M.A. Thesis. University of Hawaiʻi at Mānoa 2017

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

Do slower life history strategies reduce sociodemographic sex differences?

This study examines the relations between sociodemographic sex differences and life history strategies in the populations of Mexican States. Sex differences in anatomy and behavior was measured with traits such as educational achievement, mortality, and morbidity. The data were obtained from the Instituto Nacional de Estadística y Geografía (INEGI) and sampled from thirty-one Mexican states and the Federal District (N = 32). An extension analysis was performed selecting only the sex ratio variables that had a correlation with the slow Life History factor greater than or equal to an absolute value of .25. A unit-weighted sex ratio factor was created using these variables. Across 32 Mexican states, the correlation between latent slow life history and sex ratio was .57 (p .05). These results are consistent with our hypothesis that slower life histories favor reduced sexual dimorphism in physiology and behavior among human subnational populations. The results of the study further understanding of variations in population sex differences, male-biased behaviors toward sexual equality, and the differences among subnational (regional) populations within the United States of Mexico.   DOI:10.2458/azu_jmmss_v6i1_chavarria_miner

The Psychometric Evaluation of Human Life Histories:A Reply to Figueredo, Cabeza de Baca, Black, Garcia, Fernandes, Wolf, and Woodley (2015)

A recent critique of Copping, Campbell, and Muncer raised several issues concerning the validity of psychometric assessment techniques in the study of life history (LH) strategies. In this reply, some of our key concerns about relying on aggregated psy- chometric measures are explained, and we raise questions generally regarding the use of higher order factor structures. Responses to some of the statistical issues raised by Figueredo et al. are also detailed. We stand by our original conclusions and call for more careful consideration of instruments used to evaluate hypotheses derived from LH theory

Palaeohistology reveals a slow pace of life for the dwarfed Sicilian elephant

Altres ajuts: CERCA Programme/Generalitat de CatalunyaThe 1-m-tall dwarf elephant Palaeoloxodon falconeri from the Pleistocene of Sicily (Italy) is an extreme example of insular dwarfism and epitomizes the Island Rule. Based on scaling of life-history (LH) traits with body mass, P. falconeri is widely considered to be 'r-selected' by truncation of the growth period, associated with an early onset of reproduction and an abbreviated lifespan. These conjectures are, however, at odds with predictions from LH models for adaptive shifts in body size on islands. To settle the LH strategy of P. falconeri, we used bone, molar, and tusk histology to infer growth rates, age at first reproduction, and longevity. Our results from all approaches are congruent and provide evidence that the insular dwarf elephant grew at very slow rates over an extended period; attained maturity at the age of 15 years; and had a minimum lifespan of 68 years. This surpasses not only the values predicted from body mass but even those of both its giant sister taxon (P. antiquus) and its large mainland cousin (L. africana). The suite of LH traits of P. falconeri is consistent with the LH data hitherto inferred for other dwarfed insular mammals. P. falconeri, thus, not only epitomizes the Island Rule but it can also be viewed as a paradigm of evolutionary change towards a slow LH that accompanies the process of dwarfing in insular mammals

Disease History and Life History Predict Behavioral Control of the COVID-19 Pandemic

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The Speed of Romantic Relationship Formation: Testing Life-History and Self-Construal Explanations on the 'Timing' of Announcing Commitment.

M.A. Thesis. University of Hawaiʻi at Mānoa 2017

The Life History Model of Psychopathology Explains the Structure of Psychiatric Disorders and the Emergence of the p Factor: A Simulation Study

In recent years, tremendous progress has been made in mapping the structure of comorbidity between psychiatric disorders. In particular, empirical findings have suggested the existence of a general p factor of susceptibility to psychopathology. In the present study, simulation methods were used to test whether the observed structure of psychiatric disorders can be reproduced by the life history model of psychopathology, a recent classification model based on evolutionary theory. The assumptions of the life history model were used to generate virtual epidemiological samples, which were then analyzed with the methods used by earlier researchers. Analyses of simulated data successfully replicated the key findings by these researchers, including the emergence of the p factor and the switch from positive to negative correlation between internalizing and externalizing symptoms after inclusion of the p factor. These results offer initial support for the validity of the life history model. </jats:p