(This is in rough form and notations are a mess. I may return and clean it up and I may not.)
Why do societies repeatedly struggle with fear, hostility, and violence towards “the other”? From ancient migrations to modern debates over immigration, this pattern appears universal and stubborn. Yet, beneath the rhetoric and reaction, both biology and history reveal that turning against outsiders is not inevitable. Instead, recognizing the roots of otherism can help us transcend instincts and build a more cooperative, adaptable future.
### The Biological Basis: Built-in Boundaries and the Genetics of Aggression
Research across genetics, neuroscience, and psychology confirms that **aggression and boundary-setting are deeply rooted in human biology**, conserved across many species[1][2]. Genes that regulate neurotransmitters such as dopamine (DAT1, DAT2) and serotonin (5-HTT, MAOA) have a direct influence on how we assess threats and respond with heightened vigilance or aggression[3][4][5]. Studies using twins and adoptees reveal that **about half of the variation in human aggression comes from genetic factors, with the rest shaped by unique environmental exposures**[2][6][7][10].
Aggression has adaptive value: it protects resources, defends kin, and secures social standing[8]. These underlying biological pathways helped our ancestors survive in a world of fierce competition for mates, food, and territory[8][4]. At the same time, the same genetics and brain circuits allow for intense alliances, cooperation, and care—especially among those perceived as in-group[5][6]. *Genetics dictates the capacity, but environment and context determine its direction*[7][2].
### When Nature Meets Nurture: Institutions, Culture, and Anti-Migrant Sentiment
Though our genome primes us to mark and protect boundaries, **environmental factors—family adversity, trauma, collective stress—can greatly modulate (or inflame) these tendencies**[1][2][6]. Societies in decline or under duress often see a spike in scapegoating and exclusionary behavior, as elites and institutions seek to shore up power by amplifying “us-versus-them” narratives[1][4]. History is rich with examples: pogroms during economic collapse, xenophobia in the wake of disease or disaster, and demagogues who rise by stoking anti-other sentiment.
Yet, *the urge to defend the group is not immutable fate*. Cultures, communities, and individuals can shape which instincts are expressed—and how. Some societies have transformed their response to outsiders, moving from isolationism to openness, especially when inclusion is recognized as key to prosperity and survival.
### The Ignorance Trap: Mistaking Instinct for Inevitable Destiny
Deep-seated, difference-oriented biology **does not excuse harmful or exclusionary behavior**. Instead, it underscores the importance of understanding where these reflexes come from—so we can question their relevance in a radically interconnected world. *Defaulting to ancient instincts in the modern age risks not only moral failure but collective decline*, as history repeatedly shows that high-trust, inclusive societies out-compete those mired in division and suspicion.
Recognizing the biological basis of boundaries **frees us to work with, rather than against, our nature**. Just as self-awareness allows individuals to manage anger or fear, so can societies deliberately foster understanding, inclusion, and empathy—channeling wariness into creative collaboration rather than destructive opposition.
### Moving Forward: Seeing Ourselves in “The Other”
What does this mean for today’s debates about migrants, refugees, or anyone who doesn’t “fit” the local norm?
– **Understanding anti-migrant behaviors as both natural and malleable lets us acknowledge real fears without surrendering to them.**
– **Societies at their most creative and resilient have always been those that learn to widen the circle—turning boundaries into bridges.**
– **The project is not to erase our instincts, but to put them in context, so we can choose when and how to transcend them for the greater good.**
History and science converge on one lesson: embracing the challenge of difference, rather than recoiling from it, remains the surest path to species survival and flourishing.
## References
1. Waltes R, Chiocchetti AG, Freitag CM. The neurobiological basis of human aggression: A review on genetic and epigenetic mechanisms. *Am J Med Genet B Neuropsychiatr Genet*. 2016;171(5):650-75. [PubMed](https://pubmed.ncbi.nlm.nih.gov/26494515/)
2. Human Aggression Across the Lifespan: Genetic Propensities and Environmental Moderators. *NCBI PMC*. [PMCID: PMC3696520](https://pmc.ncbi.nlm.nih.gov/articles/PMC3696520/)
3. Genetics of aggression. *Wikipedia*. [https://en.wikipedia.org/wiki/Genetics_of_aggression](https://en.wikipedia.org/wiki/Genetics_of_aggression)
4. Genetics and epigenetics of human aggression. *ScienceDirect*. [https://www.sciencedirect.com/science/article/abs/pii/B9780128213759000050](https://www.sciencedirect.com/science/article/abs/pii/B9780128213759000050)
5. Pavlov KA, Chistiakov DA, Chekhonin VP. Genetic determinants of aggression and impulsivity in humans. *J Appl Genet*. 2012;53(1):61-82. [PubMed](https://pubmed.ncbi.nlm.nih.gov/21994088/)
6. Waltes R, Chiocchetti AG, Freitag CM. The neurobiological basis of human aggression: A review on genetic and epigenetic mechanisms. [Wiley](https://onlinelibrary.wiley.com/doi/10.1002/ajmg.b.32388)
7. Genetics of child aggression, a systematic review. *Nature*. 2024. [https://www.nature.com/articles/s41398-024-02870-7](https://www.nature.com/articles/s41398-024-02870-7)
8. Anholt RRH, Mackay TFC. Genetics of Aggression. *Annu Rev Genet*. 2012;46:145–64. [PDF](https://gwern.net/doc/genetics/heritable/2012-anholt.pdf)
9. Aggressive behavior in humans: Genes and pathways identified. *Wiley*. [https://onlinelibrary.wiley.com/doi/full/10.1002/ajmg.b.32419](https://onlinelibrary.wiley.com/doi/full/10.1002/ajmg.b.32419)
10. The genetics of violent behavior. *The Jackson Laboratory*. 2025. [https://www.jax.org/news-and-insights/jax-blog/2015/december/the-genetics-of-violent-behavior](https://www.jax.org/news-and-insights/jax-blog/2015/december/the-genetics-of-violent-behavior)
## Further Reading: Case Studies & Expansions
– **The Rwandan Genocide:** Institutional manipulation of in-group/out-group division leading to catastrophic violence.
– **Germany and the 2015 Refugee Crisis:** How leadership and public discourse can shift boundaries toward inclusion or exclusion.
– **The American Civil Rights Movement:** Systematic reduction of “othering” as a means of societal progress.
– **Urban Multiculturalism in Toronto and Singapore:** Real-world models of using diversity as strength rather than weakness.
– **Algorithmic Tribalism in Social Media:** How digital platforms can exacerbate or mitigate anti-other sentiments.
[1] https://pubmed.ncbi.nlm.nih.gov/26494515/
[2] https://pmc.ncbi.nlm.nih.gov/articles/PMC3696520/
[3] https://en.wikipedia.org/wiki/Genetics_of_aggression
[4] https://www.sciencedirect.com/science/article/abs/pii/B9780128213759000050
[5] https://pubmed.ncbi.nlm.nih.gov/21994088/
[6] https://onlinelibrary.wiley.com/doi/10.1002/ajmg.b.32388
[7] https://www.nature.com/articles/s41398-024-02870-7
[8] https://gwern.net/doc/genetics/heritable/2012-anholt.pdf
[9] https://onlinelibrary.wiley.com/doi/full/10.1002/ajmg.b.32419
[10] https://www.jax.org/news-and-insights/jax-blog/2015/december/the-genetics-of-violent-behavior