Seven and a Half Lessons about the Brain

Barrett, Lisa Feldman

Primary Category: Literature / Nonfiction

Genre: Essay

  • Date of entry: Jan-24-2021


This engaging and informative book describes the latest scientific understanding of the brain, primarily in humans, but also in other animals. The author, a leading brain researcher, writes clearly and often with humor. 

As Barrett explores the deep history of brains, she emphasizes that as much as some humans may prize thinking, the brain’s central task is not thinking but monitoring and guiding—day and night—the many systems of the body. Brains of all creatures manage a “budget” for various factors such as water, salt, glucose, blood gases, etc., to create an on-going fitness against any future threats.

Our brains and bodies are interlinked, interactive, and unified, not the “triune” brain Carl Sagan popularized in 1977. All animal brains have similar neurons, and all mammals share a “single manufacturing plan” for brain development after birth. Babies’ brains develop according to their genes and in response to their environment, especially to their caregivers. Human brains have flexible networks much like the global air-travel system and can vary from person to person and, individually, over time because of brain plasticity.           

Our individual brains influence—even create—our perceptions and relate to brains of other people through family, language, gesture, culture, and more. Barrett concludes, “Social reality is a superpower that emerges from an ensemble of human brains. It gives us the possibility to chart our own destiny and even influence the evolution of our species” (p. 123). 


This is a small format book, suitable for quick reading but complex enough for re-reading and pondering, especially because many ideas may be new to readers. 

The seven short chapters (or “lessons,” as she styles them) are introduced by an even shorter one, the “Half-Lesson: Your Brain Is Not for Thinking." She also calls them “essays,” or prose trials into the evolving nature of what we know about the brain; we can equally say there’s a dimension of the “personal essay” in that she refers to her own experience, her lab, and her daughter.           

There is humor now and then. “The size [of the brain] says nothing about how rational a species is. (If it did, our most famous philosophers might be Horton, Babar, and Dumbo)” (p. 23). Discussion of multiple stressors on a burdened “body budget,” continues with this simile: “It’s like children jumping on a bed. The bed might withstand ten kids bouncing at the same time, but the eleventh one snaps the bed frame” (p. 91).   

Of the 180 pages, 14 are for the Index, and 34 are for an Appendix of notes by page number (no footnotes.) Still further, these notes often list a website, that gives some eight screens of many, many “extended notes” for every page, often several for a single page. Readers can go as deep as they like into such detail. With primary text, notes, and extended notes, this book has three layers, even if the human brain does not. 

Eight attractive drawings give further clarity to the text. 


Houghton Mifflin Harcourt



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