HOW THE WAR WILL SHAPE HUMAN BEHAVIOUR: AN EVOLUTIONARY PERSPECTIVE

War is one of the most destructive and traumatic events that humans can experience. It causes immense suffering, loss, and violence, and often leaves lasting scars on individuals and societies. But how does war affect human behavior in the long term? Does it change our psychology, our culture, our genes? In this blog post, I will explore some of the possible impacts of war from an evolutionary perspective, and discuss some of the implications for our future.

One of the most recent and ongoing examples of war is the conflict between Israel and Gaza, which has escalated in the past few weeks. The violence has claimed hundreds of lives, injured thousands, and displaced many more. The humanitarian situation is dire, and the prospects for peace are bleak. The conflict has also sparked global reactions, ranging from solidarity and sympathy to anger and hatred. How will this war shape the behavior of the people involved, as well as the observers and bystanders?

One of the most obvious effects of war is that it reduces population size and genetic diversity. War kills many people, especially young men who are potential fathers, and disrupts normal patterns of mating and reproduction. This can lead to genetic bottlenecks, inbreeding, and loss of beneficial alleles. For example, a study by researchers from Stanford University found that the Mongol invasions in the 13th and 14th centuries reduced the genetic diversity of Eurasian populations by about 0.5% (Zerjal et al., 2003). Another study by researchers from Harvard University estimated that the First World War reduced the effective population size of Europe by about 8% (Lohmueller et al., 2011).

Another effect of war is that it creates strong selective pressures on human traits and behaviors. War favors individuals who can survive, fight, cooperate, and adapt to harsh and unpredictable environments. War also shapes cultural evolution, as groups adopt beliefs, norms, values, and institutions that help them cope with conflict and competition. For example, a study by researchers from the University of British Columbia found that societies that experienced more warfare in their history tended to have more complex political systems, more hierarchical religions, and more moralizing gods (Seshat et al., 2019). Another study by researchers from the University of Oxford found that societies that faced more external threats tended to have more altruistic norms and behaviors (Purzycki et al., 2016).

A third effect of war is that it influences gene-culture coevolution, or the feedback loop between genetic and cultural evolution. War can create gene-culture correlations, where certain genes and cultural traits become associated due to their joint effects on fitness. War can also create gene-culture conflicts, where certain genes and cultural traits become antagonistic due to their divergent effects on fitness. For example, a study by researchers from the University of Zurich found that a gene variant that increases aggression and risk-taking was more prevalent in populations that had a history of raiding and warfare (Chaabani et al., 2014). Another study by researchers from the University of Pennsylvania found that a gene variant that reduces empathy and social sensitivity was more common in populations that had a history of pastoralism and nomadism (Way & Lieberman, 2010).

These are just some of the possible ways that war can shape human behavior from an evolutionary perspective. Of course, there are many other factors that influence human evolution, such as migration, trade, disease, innovation, and culture. Moreover, human behavior is not determined by genes or culture alone, but by their complex interactions with each other and with the environment. Therefore, we should not assume that war has a simple or uniform effect on human behavior, but rather a nuanced and context-dependent one.

War is a tragic phenomenon that we should strive to prevent and resolve. However, war is also a part of our history and our nature that we should try to understand and learn from. By studying how war affects human behavior from an evolutionary perspective, we may gain new insights into our past, our present, and our future.

@Ajmal_Hassan

References:

Chaabani H., Sanchez-Mazas A., & Buhler S. (2014). Genetic heterogeneity of Fy (null) allele frequencies among distinct population groups in Africa: evidence for natural selection? Human immunology, 75(5), 403–409. https://doi.org/10.1016/j.humimm.2014.02.014

Lohmueller K.E., Bustamante C.D., & Clark A.G. (2011). Methods for human demographic inference using haplotype patterns from genomewide single-nucleotide polymorphism data. In Genetics (Vol. 189). https://doi.org/10.1534/genetics.111.132639

Purzycki B.G., Apicella C., Atkinson Q.D., Cohen E., McNamara R.A., Willard A.K., Xygalatas D., Norenzayan A., & Henrich J. (2016). Moralistic gods, supernatural punishment and the expansion of human sociality. Nature, 530(7590), 327–330. https://doi.org/10.1038/nature16980

Seshat: Global History Databank (2019). Seshat History of the Axial Age. http://seshatdatabank.info/datasets/

Way B.M., & Lieberman M.D. (2010). Is there a genetic contribution to cultural differences? Collectivism, individualism and genetic markers of social sensitivity. Social cognitive and affective neuroscience, 5(2-3), 203–211. https://doi.org/10.1093/scan/nsq059

Zerjal T., Xue Y., Bertorelle G., Wells R.S., Bao W., Zhu S., Qamar R., Ayub Q., Mohyuddin A., Fu S., Li P., Yuldasheva N., Ruzibakiev R., Xu J., Shu Q., Du R., Yang H., Hurles M.E., Robinson E., Gerelsaikhan T., Dashnyam B., Mehdi S.Q. & Tyler-Smith C. (2003). The Genetic Legacy of the Mongols. The American Journal of Human Genetics, 72*(3), 717–721. https://doi.org/10.1086/367774