Dishakjian Vahe, Fessler Daniel M T, Sparks Adam Maxwell
Department of Anthropology, University of California Los Angeles, Los Angeles, CA, USA.
Center for Behavior, Evolution and Culture, University of California Los Angeles, Los Angeles, CA, USA.
Evol Med Public Health. 2020 Dec 2;9(1):36-52. doi: 10.1093/emph/eoaa048. eCollection 2021.
Life History Theory (LHT) describes trade-offs that organisms make with regard to three investment pathways: growth, maintenance and reproduction. In light of the reparative functions of sleep, we examine sleep behaviors and corresponding attitudes as proximate manifestations of an individual's underlying relative prioritization of short-term reproduction versus long-term maintenance.
We collected survey data from 568 participants across two online studies having different participant pools. We use a mixture of segmented and hierarchical regression models, structural equation modeling and machine learning to infer relationships between sleep duration/quality, attitudes about sleep and biodemographic/psychometric measures of life history strategy (LHS).
An age-mediated U- or V-shaped relationship appears when LHS is plotted against habitual sleep duration, with the fastest strategies occupying the sections of the curve with the highest mortality risk: < 6.5 hr (short sleep) and > 8.5 hr (long sleep). LH 'fastness' is associated with increased sleepiness and worse overall sleep quality: delayed sleep onset latency, more wakefulness after sleep onset, higher sleep-wake instability and greater sleep duration variability. Hedonic valuations of sleep may mediate the effects of LHS on certain sleep parameters.
The costs of deprioritizing maintenance can be parameterized in the domain of sleep, where 'life history fastness' corresponds with sleep patterns associated with greater senescence and mortality. Individual differences in sleep having significant health implications can thus be understood as components of lifelong trajectories likely stemming from calibration to developmental circumstances. Relatedly, hedonic valuations of sleep may constitute useful avenues for non-pharmacological management of chronic sleep disorders.Lay Summary: Sleep is essential because it allows the body to repair and maintain itself. But time spent sleeping is time that cannot be spent doing other things. People differ in how much they prioritize immediate rewards, including sociosexual opportunities, versus long-term goals. In this research, we show that individual differences in sleep behaviors, and attitudes toward sleep, correspond with psychological and behavioral differences reflecting such differing priorities. Orientation toward sleep can thus be understood as part of the overall lifetime strategies that people pursue.
生活史理论（LHT）描述了生物体在生长、维持和繁殖这三条投资途径上所做的权衡。鉴于睡眠的修复功能，我们将睡眠行为及相应态度作为个体在短期繁殖与长期维持方面潜在相对优先级的直接表现进行研究。
我们通过两项针对不同参与者群体的在线研究，收集了568名参与者的调查数据。我们使用分段回归模型、分层回归模型、结构方程模型和机器学习相结合的方法，来推断睡眠时间/质量、睡眠态度与生活史策略（LHS）的生物人口统计学/心理测量指标之间的关系。
当将生活史策略与习惯性睡眠时间作图时，会出现年龄介导的U形或V形关系，最快的策略出现在曲线中死亡风险最高的部分：<6.5小时（短睡眠）和>8.5小时（长睡眠）。生活史“速度”与嗜睡增加和整体睡眠质量较差相关：睡眠开始潜伏期延迟、睡眠开始后更多觉醒、更高的睡眠 - 觉醒不稳定性以及更大的睡眠时间变异性。对睡眠的享乐主义评价可能介导生活史策略对某些睡眠参数的影响。
在睡眠领域，可以对将维持置于次要地位的成本进行参数化，其中“生活史速度”与衰老和死亡率较高相关的睡眠模式相对应。因此，具有重大健康影响的睡眠个体差异可被理解为可能源于对发育环境校准的终身轨迹的组成部分。相关地，对睡眠的享乐主义评价可能构成慢性睡眠障碍非药物管理的有用途径。
睡眠至关重要，因为它能让身体进行自我修复和维持。但用于睡眠的时间就无法用于做其他事情。人们在将包括社交性机会在内的即时回报与长期目标的优先级排序上存在差异。在本研究中，我们表明睡眠行为和对睡眠的态度的个体差异，与反映这种不同优先级的心理和行为差异相对应。因此，对睡眠的取向可被理解为人们所追求的整体终身策略的一部分。
