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7½ Lessons for the Brain, Barrett (2020)

Study notes for this short, pithy book about the brain, our relationship with it, and the nature of reality.

½ Your Brain is Not for Thinking

Your brain’s most important job is not thinking; it is to control your body – to manage allostasis – ie. predicting and preparing to meet the body’s energy needs (prediction beats reaction in nature) before they arise, so you can efficiently make worthwhile movements and survive. Your brain is the command center that supervises, regulates, and protects the systems and subsystems that comprise your entire body.

1. You Have One Brain (not Three)

Paul MacLean’s three-layered brain – neocortex (rational), limbic (emotional), lizard (survival) – is a modern myth that persists in popular culture because of its accessibility and our ego; the conflict between the rational and the emotional is based on this belief. However, this is not borne out by science – the rational/emotional dichotomy is a false one – there is only one brain, and its rational behavior consists of making a good body-budgeting investment in a given situation.

2. Your Brain is a Network

A network (a tree-like structure of neurons, synapses, dendrites, axons, etc.) is the best scientific description of a brain today – a physical structure that is capable of reconfiguring itself (often very quickly) to integrate vast amounts of information efficiently. The brain is considered a complex system, able to configure itself into an enormous number of distinct neural patterns. It is capable of degeneracy – almost like redundancy, instead of the same set of neurons being responsible for a certain action, different sets of neurons are capable of this task. Complex brains remember more, are more creative and adaptable, and are also more resilient to injury. Note that other species on Earth also have brains with high complexity.