7 1/2 Lessons about the brain

By Lisa Feldman Barrett

Thanks to my friend, Dennis Leas, for sharing Lisa Feldman Barrett’s 2020 book,  7 1/2 Lessons About the Brain. It's a remarkable book, filled with valuable lessons about the complexities of the human brain and reminders that the brain operates as one marvelous organ (often networking with other brain-like organs in the human body), not isolated parts that simply "network with one another". Here is a brief summary of each of the chapters of the book:

1. Half Lesson: In the half lesson, Barrett begins her journey with Amphioxus,  a creature that evolved around 500 million years ago important to understanding the evolution of vertebrae, and critical to the central thesis of Barrett’s book, that the brain’s most important job is allostasis, i.e.,” automatically predicting and preparing to meet the bodies needs before they arise.” This should not surprise us, since most of these processes happen without us having to think about them. And yet, a common misperception among us all is that the primary purpose of our brain is to “think”!

2. Lesson One dismisses the idea of the "triune" brain, the idea that "the human brain ended up with three layers--one for surviving, one for feeling, and one for thinking". Genetic testing has revealed “that neurons from two species of animals can look very different but still contain the same genes,  suggesting that those neurons have the same evolutionary origin. If we find the same genes in certain human and rat neurons, for example, then similar neurons with those genes were most likely present in our last common ancesters…The biological building blocks are the same; what differs is the timing. For example, the stage that produces neurons for the cerebral cortex in humans runs for a shorter time in rodents and a much shorter time in lizards, so your cerebral cortex is large, a mouse’s is smaller, and an iguana’s is tiny (or nonexistent—it’s debatable)."

3. Lesson Two reminds us how complex and holistic the brain is, it’s remarkable plasticity, and many similar concepts we discussed in chapter 10 about how the brain works to reconstruct rather than store memories like a hard drive.

4. Lesson Three focuses on how brains develop, a process Barrett describes as “tuning and pruning”. Areas of the brain tune in to activities one experiences through their senses, strengthening neuronal connections between existing neurons (i.e., plasticity) and building new cells in a “bush-like” growth and development of the  brain. Similarly, cells that are not used die off, saving energy that the brain can put to more efficient use elsewhere. Barrett suggests that this “tuning and pruning process may help to explain why children are more adept at learning new languages, as children learn to “tune in” to the uniquely different sounds of different languages.

5. Lesson Four explores the neurological processes, which Barrett calls “predictions...your brain having a conversation with itself. A bunch of neurons make their best guess aboout what will happen in the immediate future based on whatever combination of past and present that your brain is currently conjuring." Barrett's discussion seems to directly relate to the discussion in chapter one about how we create stories (pp 8-9): how precisely we detail the world of the play versus how much we ask our audience to create themselves. In essence, how much we give the audience versus how much we ask them to "predict" for themselves. We also discuss a concept that appears to be related to prediction in chapter ten as the result of how our autobiographical memories interact with the world to influence our perception of that world.

6. Lesson Five may serve as the basis of the discussion we had in MAAC chapters five and six about how entrainment influences bodily functions such as pulse, heart rate, skin conductance, etc. Barrett teaches us that our senses influence our brain and bodily functions far more than just entrainment, especially in regards to to language and social interactions. Our brains "secretly work with other brains".

7. In Lesson Six, Barrett reminds us how important culture and learning are to the way the brain works. Barrett extends this concept to argue that every brain is unique and different, separating mind from brain. We encounter the same problem in Music as a Chariot, which we discuss in the introduction on page 8: the mind-and its “culturally acquired characteristics” is much too broad a subject to hope to use to attempt to provide commonalities in our perception of sound and music. Instead we rely on biological functions and evolutionary evidence, based in peer-reviewed research to provide the framework for a discussion of my own aesthetic, which is by definition as uniquely different as the number of composers and sound designers in the universe.

8. Lesson Seven offers up what may be some of the most interesting ideas of the book. Barrett introduces five “C’s”, a “suite of abilities” that, when combined are unique to humans: creativity, communication, copying, cooperation and compression. Our entire book in one sense is about the specific biological origins of creativity that, as Barrett says, “allows us to make art and music.” We, of course, narrowed the scope of our book by limiting our discussion to exclude as much as possible, the sort of communication Barrett discusses. We discussed copying and Merlin Donald’s proposed origins as one of the three great breakthroughs in human consciousness in MAAC chapter five. We discussed the major leap forward humans took in cooperation in MAAC chapter six, Campfire Songs. And finally, we introduced some of the theories related to compression in MAAC chapter ten when we discussed how chunking works in relation to memory. Barrett includes a really useful explanation about how neurons in the brain create this sort of compression and brings these ideas together to help us understand the concept of abstraction, our ability to perceive meaning in abstract objects, concepts, etc., and in how we humans construct social realities.

9. In the Appendix, Barrett raises a central concern of the book, that it is intended for the lay person, and therefore does not separate research from opinion in a clearly unambiguous way. Some of the conclusions Barrett reaches are still debated, and it’s in the appendix that Barrett lays out the debates and the reasons for her conclusions. For example, in Chapter two, Barrett states as fact that the brain has 128 billion neurons without citation. Then in the appendix, Barrett acknowledges that there are different points of view on this assessment, and gives her reasons why she chooses this particular number. This can lead the reader to approach the discussions with caution, which is always recommended anyway. It can be hard to separate research from opinions. But Barrett has extensive and stellar credentials as a neuroscientist that include a Distinguished Professorship, an appointment at Harvard Medical school, a recipient of a Guggenheim Fellowship, and much more, which certainly leads one to take even her opinions very seriously! And when in doubt, Barrett has published a full list of references at https://sevenandahalflessons.com.