Alan Silburn ^*

• Western Sydney University, Penrith, Australia

A human's physical, social, and psychological attributes are all challenged when having to function in extreme and unusual environments. Thus, individuals inhabiting them, need to possess certain characteristics to ensure performance and successful adaptation within their situation and surroundings (Barnett & Kring, 2003;Bishop, 2004). The following will define the factors that contribute to an environment being extreme and how they affect the humans inhabiting it. With this definition established, an assessment will be conducted to determine the suitability of an individual to inhabit diverse environments and how mitigation strategies at recruitment may enhance human functioning when inhabiting extreme environments.An extreme environment can be defined as an environment that poses an increased risk to life or is hazardous to a subjected organism to which it is not suited (Boyd, Krell & Rajakaruna, 2016). For example, sea life that has evolved and adapted to the hyperbaric conditions of the ocean's abyss, what humans consider an extreme environment, is considered optimal to sustain life and leaving this environment would prove fatal (Wingfield, Kelley & Angelier, 2011). However, unlike others, the human species has become proficient at tailoring the conditions to suit our natural physiological demands to be able to thrive in almost every extreme environment accessible to us. These conditions, or physical characteristics, are those that deviate from the requirements to maintain human functioning at an optimal level. These extreme conditions are often associated with high or low temperatures, isolation, alterations in light-dark cycling and circadian rhythms, physical discomfort, reduced visibility, or stresses of sudden disaster (Suedfeld, 2001).Although the human species has occupied and thieved in extreme environments (Barnett & Kring, 2003), the often harsh and demanding conditions have significant impacts on the human's physical and psychological functioning which all humans may not be suited to endure.Extreme environments come in various forms, extending beyond naturally harsh physical landscapes to include situations shaped by social, cultural, and even organizational pressures. For instance, while the cold, isolation, and oxygen-deprived conditions of polar regions or high-altitude mountains are quintessential examples, other environments, like those affected by climate change-induced heatwaves, rising sea levels, and sudden natural disasters, also qualify as extreme due to the immediate threat they pose to human health and safety (Thompson et al., 2023). Climate change is increasingly creating environments that test human resilience and adaptability, not only by directly exposing individuals to hazardous conditions but also by disrupting entire ecosystems and communities (Myers & Patz, 2009). In this sense, environments that were once manageable for human habitation may shift into the extreme category due to evolving climate pressures.Similarly, social and cultural dynamics can produce extreme environments that challenge human functioning in less visible but equally impactful ways. For example, individuals operating in active war zones face profound psychological and emotional stress in addition to physical dangers. In such settings, people must endure constant threats of violence, potential loss of life, and the trauma associated with witnessing or experiencing violence firsthand. The unpredictable nature of war, combined with the intensity of emotional strain and limited access to basic necessities, creates an environment that severely tests psychological resilience. Just as physically harsh landscapes challenge endurance, warzones challenge mental fortitude, as individuals navigate a high-stakes environment where their safety, emotional stability, and well-being are persistently under threat (Fontana & Rosenheck, 1999).Given the diversity of extreme environments, certain personality traits may enhance an individual's ability to function and adapt successfully within these varied settings. Traits such as high-stress tolerance, emotional stability, and adaptability are particularly valuable for individuals facing physically harsh conditions, such as those found in space or in disaster zones (Bartone et al., 2018). In socially adverse environments, such as conflictridden regions, qualities like resilience, strong interpersonal skills, and a high capacity for empathy are crucial (Fletcher & Sarkar, 2013). While physical endurance may be paramount in one setting, psychological resilience and adaptability may take precedence in another, indicating that specific environments demand unique personality profiles to ensure optimal performance and well-being. These attributes are further presented in Table 1. For many of us, having access to modern conveniences that provide a comfortable and stable environment in our homes and places of work bestows a quality of life that is unsurpassable (Davis & Buskist, 2008, pp. 210-218). However, there are select individuals who choose to live and operate in the less-than-favourable conditions of extreme environments. Individuals who choose to live and work in extreme environments are often driven by a sense of purpose, adventure, or cultural tradition. Professions like military service, deep-sea commercial diving, and scientific field research attract those committed to impactful work in high-stakes settings, while adventurers, such as mountaineering guides and polar researchers, are drawn to pushing personal limits and exploring the unknown. Cultural traditions also play a role; Indigenous groups like the Inuit in the Arctic, Bedouins in the desert, and Sherpa of Nepal have adapted to their harsh landscapes for generations, finding identity and purpose in these environments.These individuals must contain certain characterises that make them uniquely suited to adapt to the complex, challenging, and often dangerous activities that are required in extreme environments (Davis & Buskist, 2008, pp. 210-218). Therefore, during the recruitment process, a personality profile should be formulated to suggest if a person is suitable for the required environmental deployment.Personality profiling in personnel recruitment has been utilised by countless organisations to determine if that person has 'the right stuff' by weighing them against predetermined criteria permitting a select-out/in approach to personnel selection. To gather this information, the selected cohort is asked to complete a personality questionnaire based on the International Personality Item Pool that addressed their 'Big 5' personality dimensions as these traits are the most commonly used to model personality in academic psychology (Goldberg et al. 2006). These dimensions of personality determine a person's degree of neuroticism, extraversion, agreeableness, conscientiousness, and openness to experience (Goldberg et al. 2006).Following the questionnaire, individual results are displayed and classified relative to the standard deviation of the cohort for the five categories of personality dimensions.Scores were determined as low, moderately low, average, moderately high, and high depending on the deviation from the mean.After the data is collated, the select-out phase excluded those with the risk of poor psychosocial adaptation and inconsistencies in task performance. Commonly, those excluded meet psychiatric criteria or may be at high risk for such disorders, present with inadequate preparation, or possess a problematic life history as antisocial or unpredictable behaviours may jeopardise the intended objective (John Paul, 2014). Regarding the questionnaire results, those that scored low on agreeableness are deemed as being highly critical and aggressive and those low on conscientiousness are deemed as being impulsive and disorganised, thus presenting a risk of antisocial or unpredictable behaviours and are subsequently excluded from the recruitment process.Secondly, criteria are utilised to select-in individuals with desirable characteristics in an attempt to predict the adaptation, reliability, and performance in these environments (John Paul, 2014). These desirable attributes are noticeable in people who are conscientious, emotionally stable, less anxious and who tolerate stress better than the general population (Collado et al. 2018) and thus would therefore not be as susceptible to depression, irritability, aggressive behaviour, insomnia, difficulty in concentration, or absentmindedness common to those in extreme or isolated environments (John Paul, 2014). Hence, the select-in criteria are often set to those as having high levels of conscientiousness, high levels of openness to experience, and low levels of neuroticism as these individuals would reflect the desirable attributes of being careful and diligent, emotionally stability, and would be more flexible in dealing with non-traditional challenges and problem-solving (Parr, Lanza & Bernthal, 2016).The final personality dimension of extroversion was considered a neutral classification that could be used in selection to reflect the nature of the mission and the type of extreme environment in question. For example, those with high extroversion results are suited for group work such as expedition teams, multi-agency deployments, or leadership roles. In contrast, this need for interpersonal and organisational connection is a flaw in environments of low social contact such as polar stations, spaceflight, hyperbaric research and other individual or small team missions that are more suited to those of a low extroversion level. Extreme environments, by their nature, place extraordinary demands on human capabilities across physical, social, and psychological domains. Therefore, identifying individuals with the "right stuff" is paramount for mission success and individual well-being.Personality profiling, as part of a comprehensive selection process, plays a vital role in assessing an individual's suitability for these challenging contexts. By evaluating traits such as agreeableness, conscientiousness, emotional stability, and adaptability, organisations can better predict an individual's capacity to not only survive but also thrive in extreme environments. Abbreviations: Not applicable  Ethics approval and consent to participate: This study did not require ethical approval as it involved a retrospective analysis of publicly available and anonymized information, with no direct involvement of human subjects. Consent for publication: The author consents for the publication of this article. Availability of data and materials: Not applicable  Competing Interests: The author declares that they have no known competing interests or personal relationships that could have appeared to influence the work reported in this paper. Funding: The author declares that they did not receive funding for this article. Authors' contributions: The author solely contributed to the conception, design, analysis, and drafting of the manuscript. Acknowledgements: Not applicable