Mathematical Modeling of Social Systems Department, Institute for Research on Applied Mathematics and Systems, National Autonomous University of Mexico, Mexico City, Mexico.
Am J Biol Anthropol. 2022 Sep;179(1):73-84. doi: 10.1002/ajpa.24588. Epub 2022 Jul 21.
To evaluate three of the main verbal models that have been proposed to explain the relationship between fluctuating asymmetry and fitness in humans: the "good genes," the "good development," and the "growth" hypotheses.
A formal model was generated for each verbal model following three steps. First, based on the literature, a theoretical causal model and the theoretical object of inquiry were outlined. Second, an empirical causal model and the targets of inference were defined using observational data of facial asymmetries and life-history traits related to fitness. Third, generalized linear models and causal inference were used as the estimation strategy.
The results suggest that the theoretical and empirical assumptions of the "good genes" hypothesis should be reformulated. The results were compatible with most of the empirical assumptions of "the good development" hypothesis but suggest that further discussion of its theoretical assumptions is needed. The results were less informative about the "growth" hypothesis, both theoretically and empirically. There was a positive association between facial fluctuating asymmetry and the number of offspring that was not compatible with any of the empirical causal models evaluated.
Although the three hypotheses focus on different aspects of the link between asymmetry and fitness, their overlap opens the possibility of a unified theory on the subject. The results of this study make explicit which assumptions need to be updated and discussed, facilitating the advancement of this area of research. Overall, this study elucidates the potential benefit of using formal models for theory revision and development.
评估三种主要的口头模型，这些模型被用来解释人类中波动不对称与适应度之间的关系：“好基因”、“良好发育”和“生长”假说。
为每个口头模型生成了一个正式模型，分为三个步骤。首先，基于文献，概述了理论因果模型和理论研究对象。其次，使用与适应度相关的面部不对称和生活史特征的观察数据，定义了经验因果模型和推理目标。最后，使用广义线性模型和因果推理作为估计策略。
结果表明，“好基因”假说的理论和经验假设应该重新制定。结果与“良好发育”假说的大多数经验假设相兼容，但表明需要进一步讨论其理论假设。理论和经验上，“生长”假说的结果都不太有信息。面部波动不对称与生育子女数量之间存在正相关，这与评估的任何经验因果模型都不兼容。
尽管这三个假说侧重于不对称与适应度之间联系的不同方面，但它们的重叠为该主题的统一理论提供了可能性。本研究的结果明确了需要更新和讨论的假设，促进了该研究领域的发展。总的来说，本研究阐明了使用正式模型进行理论修正和发展的潜在好处。
