Combat stress in a small-scale society suggests divergent evolutionary roots for posttraumatic stress disorder symptoms

The Nature of Combat Stress Development During Military Operations and Psychotherapy in Extreme Situations

ABSTRACT

The purpose of the research work is the theoretical and empirical analysis of the study of the nature of combat stress in military personnel and the assessment of psychotherapeutic methods of providing psychological assistance in extreme situations. The authors used the following methods to achieve this goal: method of analysis and synthesis, hermeneutic method, testing method, comparative method, and generalization method. The results of the research work have revealed the meaning of traumatic stress, psychological trauma, and combat mental trauma, and explained the concept of combat stress and the dynamics of its growth. The findings identified the factors of posttraumatic stress syndrome and its prevalence, tracked down the dynamics of psychoemotional disorders, and revealed the importance of military psychological selection and determination of combat readiness. The authors established the main tasks of a staff psychologist in working with military personnel, conducted an empirical study of the nature of combat stress in the military, observed main psychotherapeutic tools for the prevention of negative mental states in combat conditions, and investigated self-regulation techniques of emotional, physical, and mental health. The practical significance of the scientific work lies in the modern coverage of the phenomenon of combat stress and the classification of effective psychotherapeutic methods that will ensure the sustainable psychological preparation of the soldiers for extreme situations.

How evolutionary science can help us understand vaccine refusal in the COVID-19 pandemic

Unvaccinated people have a mortality rate from COVID-19 that is 32-fold that of fully vaccinated people. Yet, in the UK, more than 4% of adults have not accepted a vaccine to protect them against COVID-19 and at the time of writing only 73% of people were fully vaccinated. Psychological and societal factors underlying vaccine hesitation or refusal are complex. In this paper, we use evolutionary science to help explain how vaccine refusal can be the result of an historic adaptation to protect against the repetition of past trauma, including, for many, that of systemic racism and/or deprivation, and misguided attempt to preserve fertility. We discuss some resulting cognitive biases and conclude with recommendations for practice.

What is the expected human childhood? Insights from evolutionary anthropology

In psychological research, there are often assumptions about the conditions that children expect to encounter during their development. These assumptions shape prevailing ideas about the experiences that children are capable of adjusting to, and whether their responses are viewed as impairments or adaptations. Specifically, the expected childhood is often depicted as nurturing and safe, and characterized by high levels of caregiver investment. Here, we synthesize evidence from history, anthropology, and primatology to challenge this view. We integrate the findings of systematic reviews, meta-analyses, and cross-cultural investigations on three forms of threat (infanticide, violent conflict, and predation) and three forms of deprivation (social, cognitive, and nutritional) that children have faced throughout human evolution. Our results show that mean levels of threat and deprivation were higher than is typical in industrialized societies, and that our species has experienced much variation in the levels of these adversities across space and time. These conditions likely favored a high degree of phenotypic plasticity, or the ability to tailor development to different conditions. This body of evidence has implications for recognizing developmental adaptations to adversity, for cultural variation in responses to adverse experiences, and for definitions of adversity and deprivation as deviation from the expected human childhood.

Socioeconomic status effects on health vary between rural and urban Turkana

Background and objectives

Understanding the social determinants of health is a major goal in evolutionary biology and human health research. Low socioeconomic status (often operationalized as absolute material wealth) is consistently associated with chronic stress, poor health and premature death in high-income countries. However, the degree to which wealth gradients in health are universal—or are instead made even steeper under contemporary, post-industrial conditions—remains poorly understood.

Methodology

We quantified absolute material wealth and several health outcomes among a population of traditional pastoralists, the Turkana of northwest Kenya, who are currently transitioning toward a more urban, market-integrated lifestyle. We assessed whether wealth associations with health differed in subsistence-level versus urban contexts. We also explored the causes and consequences of wealth-health associations by measuring serum cortisol, potential sociobehavioral mediators in early life and adulthood, and adult reproductive success (number of surviving offspring).

Results

Higher socioeconomic status and greater material wealth predicts better self-reported health and more offspring in traditional pastoralist Turkana, but worse cardiometabolic health and fewer offspring in urban Turkana. We do not find robust evidence for either direct biological mediators (cortisol) or indirect sociobehavioral mediators (e.g. adult diet or health behaviors, early life experiences) of wealth–health relationships in either context.

Conclusions and implications

While social gradients in health are well-established in humans and animals across a variety of socioecological contexts, we show that the relationship between wealth and health can vary within a single population. Our findings emphasize that changes in economic and societal circumstances may directly alter how, why and under what conditions socioeconomic status predicts health.

Lay Summary

High socioeconomic status predicts better health and more offspring in traditional Turkana pastoralists, but worse health and fewer offspring in individuals of the same group living in urban areas. Together, our study shows that under different economic and societal circumstances, wealth effects on health may manifest in very different ways.