Humankind has a single brain architecture

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A note for Lesson no. 6, "Brains Make More Than One Kind of Mind," in Seven and a Half Lessons About the Brain by Lisa Feldman Barrett.
Some context from page 100‌‌ is:

...humankind has a single brain architecture...

When I write that humans have a single brain architecture, I am focusing on some large-scale structural features of the human brain that are shared by most humans, even though the microwiring of human brains differs across people and across the lifetime of single person.

For example, the general layout of the human brain is guided by a set of ancient genes that determine the head-to-tail organization of an animal's body, called Homeobox genes or "Hox" genes (for a review, see [1][2]). Hox genes seem to function like a biological GPS, ensuring that embryonic cells migrate to their correct positions so that body parts (including segments of the brain) develop in specific locations. Normally, across the course of evolution, genes mutate and change due to both natural selection and random reasons (as cells replicate during the lifetime of an animal).

Hox genes are hundreds of millions of years old. The fact that homologous Hox genes can be found in worms, flies, and humans, suggesting that these genes are under strong selection pressure not to change. That is, embryos with mutated Hox genes may never fully develop, or if they are developed and born, they may die before reproducing.


  1. Gee, Henry. 2018. Across the Bridge: Understanding the Origin of the Vertebrates. Chicago, IL: University of Chicago Press.
  2. Striedter, Georg F., and R. Glenn Northcutt. 2020. Brains Through Time: A Natural History of Vertebrates. New York: Oxford University Press.