Words&Dirt

Summary:

Lisa Feldman Barrett’s Seven and a Half Lessons About the Brain is an exceptionally lucid and commendable contribution to popular neuroscience. In this series of concise, highly-accessible essays, Barrett synthesizes a huge field of academic knowledge in a fashion that any literate person can enjoy and benefit from. Her central thesis is that the brain is not primarily an organ for thinking or understanding the world as it is, but rather a bio-machine evolved to manage our “body budget” through a predictive process known as allostasis: “automatically predicting and preparing to meet the body’s needs before they arise” (8). Barrett does an excellent job of describing the character and consequences of the brain’s allostatic nature, demonstrating how it influences psychosocial development, neurodiversity, the construction of social reality, and other topics. Full of humanistic insights, clever quips, and ethical elegance, Seven and a Half Lessons is that very rare science book that I would unreservedly recommend to anyone, regardless of their personal reading preferences or academic background.

Key Concepts and Notes:

• Given my familiarity with the basics of neuroscience, I honestly wasn’t expecting to learn as much new information as I did from this book. Barrett’s talent for scientific metaphor is especially edifying, particularly her “body budget” analogy for allostasis, her comparison of brain activity to global airport systems, and her use of tree/plant imagery to illustrate the “tuning” and “pruning” of neural networks.
• Like other great neuroscientists before her (e.g. Antonio Damasio), Barrett continues the important work of arguing that rationality and emotion are not oppositional forces struggling for dominance over human nature, but rather two essential components of the human organism that depend on one another to function optimally.
• Barrett smartly includes contemporary research on animal intelligence that reveals the human brain and intellect as basically unexceptional. Barrett celebrates humanity’s cognitive gifts but also repeatedly reminds us that they don’t make us fundamentally different from or superior to our fellow animals.
• Barrett doesn’t shy away from the sociopolitical and economic consequences of modern neuroscience, but she also doesn’t come off as overly preachy. This book includes balanced but emphatic passages about why poverty/scarcity is so damaging to individuals and societies, the benefits and drawbacks of tribalism, the critical importance of education and social connection throughout one’s lifespan, the evolutionary underpinnings and survival value of neurodiversity, the tension between personal freedom and collective responsibility, and the double-edged dynamics of our constructed social realities.
• I had a few quibbles with Barrett’s arguments along the way, the most notable of which was my disagreement with her position that ”the human mind has no universal defining features” (104). After dropping that statement, Barrett then spends a few pages discussing the closest thing we have to “a universal mental feature,” which is mood/affect (104). At the end of that section, she says that “Even though every human culture produces minds that feel pleasure, displeasure, calmness, and agitation, we don’t necessarily agree on what makes us feel these things” (107). In my view, this means that rudimentary experiential phenomena such as pleasure/displeasure and calmness/agitation are precisely the “universal defining features” that Barrett denies. It doesn’t matter that these features can be activated or suppressed by a variety of stimuli and are highly sensitive to cultural idiosyncrasies––what matters is that everyone has them. This could just boil down to semantics about the proper meaning of “universal” in this context, but I think it’s worth pushing on, both because I believe some version of “soft universalism” is supported by Barrett’s own evidence (and neuroscience in general), and also because having something universal about human nature provides excellent ethical bedrock for a continued commitment to humanism and the development of a strong global identity shared by all people. Maybe this is just motivated reasoning on my part; I’m not entirely sure!

Favorite Quotes:

Why did a brain like yours evolve? That question is not answerable because evolution does not act with purpose––there is no “why.” But we can say what is your brains most important job. It’s not rationality. Not emotion. Not imagination, or creativity, or empathy. Your brain’s most important job is to control your body––to manage allostasis––by predicting energy needs before they arise so you can efficiently make worthwhile movements and survive. Your brain continually invests your energy in the hopes of earning a good return, such as food, shelter, affection, or physical protection, so you can perform nature’s most vital task: passing your genes to the next generation.

In short, your brain’s most important job is not thinking. It’s running a little worm body that has become very, very complicated. (10-1)

Neurons are grouped into clusters that are like airports. Most of the connections in and out of a cluster are local, so, like an airport, the cluster serves mostly local traffic. In addition, some clusters serve as hubs for communication. They are densely connected to many other clusters, and some of their axons reach far across the brain and act as long-distance connections. Brain hubs, like airport hubs, make a complicated system efficient. They allow most neurons to participate globally even as they focus more locally. Hubs form the backbone of communication throughout the brain.

Hubs are supercritical infrastructure. When a major airport hub like Newark or London’s Heathrow goes down, flight delays and cancellations ripple across the world. So imagine what happens when a brain hub does down. Hub damage is associated with depression, schizophrenia, dyslexia, chronic pain, dementia, Parkinson’s disease, and other disorders. Hubs are points of vulnerability because they are points of efficiency––they make it possible to run a human brain in human body without depleting a body budget. (34-5)

Have you ever seen a friend’s face in a crowd, but when you looked again, you realized it was a different person? Have you ever felt your cell phone vibrate in your pocket when it didn’t? Have you ever had a song playing in your head that you couldn’t get rid of? Neuroscientists like to say that your day-to-day experience is a carefully controlled hallucination, constrained by the world and your body but ultimately constructed by your brain. It’s not the kind of hallucination that sends you to the hospital. It’s an everyday kind of hallucination that creates all your experiences and guides all your actions. It’s the normal way that your brain gives meaning to your sense data, and you’re almost always unaware that it’s happening.

I realize that this description defies common sense, but wait: there’s more. This whole constructive process happens predictively. Scientists are now fairly certain that your brain actually begins to sense the moment-to-moment changes in the world around you before those light waves, chemicals, and other sense data hit your brain. The same is true for moment-to-moment changes in your body––your brain begins to sense them before the relevant data arrives from your organs, hormones, and various bodily systems. You don’t experience your senses this way, but it’s how your brain navigates the world and controls your body. (71-2)

When your predicting brain is right, it creates your reality. When it’s wrong, it still creates your reality, and hopefully it learns from its mistakes. (76)

It’s impossible to change your past, but right now, with some effort, you can change how our brain will predict in the future. You can invest a little time and energy to learn new ideas. You can curate new experiences. You can try new activities. Everything you learn today seeds your brain to predict differently tomorrow. (78)

Best thing for your nervous system is another human. The worst thing for your nervous system is also another human. The situation leads us to a fundamental dilemma of the human condition. Your brain needs other people in order to keep your body alive and healthy, and at the same time, many cultures strongly value individual rights and freedoms. Dependence and freedom are naturally in conflict. (93)

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. We can make abstract concepts, share them, weave them into a reality, and conquer just about any environment––natural, political, or social––as long as we work together. We have more control over reality than we might think. We also have more responsibility for reality then we might realize.

Every type of social reality is a dividing line. Some dividing lines help people, such as driving laws that prevent head-on collisions. Other dividing lines benefit some people and hurt others, such as slavery and social class. People debate the morality of such dividing lines, but like it or not, each of us bears some responsibility every time we reinforce them. A superpower works best when you know you have it. (123)

Once upon a time, you were a little stomach on a stick, floating in the sea. Little by little, you evolved. You grew sensory systems and learned that you were part of a bigger world. You grew bodily systems to navigate that world efficiently. And you grew a brain that ran a budget for your body. You learned to live in groups with all the other little brains-in-bodies. You crawled out of the water and onto land. And across the expanse of evolutionary time––with the innovation that comes from trial and error and the deaths of trillions of animals––you ended up with a human brain. A brain that can do so many impressive things but at the same time severely misunderstands itself…

Our kind of brain isn’t the biggest in the animal kingdom, and it’s not the best in any objective sense. But it’s ours. It’s the source of our strengths and our foibles. It gives us our capacity to build civilizations and our capacity to tear down each other. It makes us simply, imperfectly, gloriously human. (124-5)

Rating: 9/10