Seven and a Half Lessons About the Brain1 is the second book by neuroscientist Lisa Feldman Barrett. The lessons offer a concise overview of what is known about the human brain and attempt to overturn what Barrett views as popular myths and misunderstandings about this most fascinating organ.
Your Brain’s Most Important Job
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 brain’s 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.
This is the ‘half lesson’ in Seven and a Half Lessons About the Brain. Barrett argues that rather than thinking, our brains’ primary function is allostasis, or ‘body budgeting’: the process of allocating the body’s scarce resources effectively in order to ensure our survival and reproduction.
So we’re all economists, basically. (Don’t tell Nassim Nicholas Taleb.)
‘One of the Most Successful and Widespread Errors in All of Science’
Barrett goes on to debunk what she describes as ‘one of the most successful and widespread errors in all of science.’ She is referring to the ‘triune brain story’: the view that our brains are comprised of three parts; a lizard brain (instinctual ‘survival brain’), limbic system (mammalian ‘emotional brain’), and neocortex (human ‘rational brain’).
[Y]ou don’t have an inner lizard or an emotional beast-brain. There is no such thing as a limbic system dedicated to emotions. And your misnamed neocortex is not a new part; many other vertebrates grow the same neurons that, in some animals, organize into a cerebral cortex if key stages run for long enough. Anything you read or hear that proclaims the human neocortex, cerebral cortex, or prefrontal cortex to be the root of rationality, or says that the frontal lobe regulates so-called emotional brain areas to keep irrational behavior in check, is simply outdated or woefully incomplete. The triune brain idea and its epic battle between emotion, instinct, and rationality is a modern myth.
The Brain in Context
If there was no danger and your body prepared to flee anyway, would that be irrational behavior? It depends on context. Suppose you’re a soldier in a war zone, where threats appear on a regular basis. It’s appropriate for your brain to frequently predict threat. It may sometimes guess incorrectly and flood you with cortisol when there’s no danger. In one sense, we could view this false alarm as needless spending of resources that you may need later and therefore irrational. But in a war zone, this false alarm may be rational from a body-budgeting standpoint. You might waste a bit of glucose or other resources in the moment, but over the long run, you are more likely to survive.
If you return home from war to a safer environment but your brain continues to false-alarm, as happens in post-traumatic stress disorder, that behavior could still be considered rational. Your brain is protecting you from threats it believes are present, even though the frequent withdrawals decimate your body budget. The problem is your brain’s beliefs; they are not a good fit for your new environment, and your brain hasn’t adjusted yet. What we call mental illnesses, then, may be rational body-budgeting for the short term that’s out of sync with the immediate environment, the needs of other people, or your own best interests down the road. (emphasis added)
It is nice to see Barrett emphasise this point. So often, the desire to label an individual ‘irrational’ or ‘abnormal’ stems from an inability to recognise the larger context in which the person lives. Those who fixate on a specific behaviour, without considering the context in which the behaviour arose, are fumbling in the dark.
Debunking Myths (And Perpetuating Others)
Although Barrett argues vigorously against some modern myths about the brain, she also perpetuates one.
Hub damage [i.e. neurological damage] is associated with depression, schizophrenia, dyslexia, chronic pain, dementia, Parkinson’s disease, and other disorders.
Here, she conflates actual neurological disorders like Parkinson’s and dementia, with the psychiatric diagnoses ‘schizophrenia’ and ‘depression’. Barrett offers no evidence for this. Probably because there is no solid evidence that these labels represent underlying brain diseases. This is unfortunate given that in a section of the previous chapter (quoted above), she suggested that ‘mental illness’ is a rational response to environmental stressors.
On Choice and Responsibility
Unlike what appears to be the position of an increasing number of scientists (e.g. Robert Sapolsky, Sam Harris), Barrett does not identify as a staunch determinist i.e., someone who considers free will an illusion. She instead offers a more nuanced perspective on what we can and cannot control.
Your actions today become your brain’s predictions for tomorrow, and those predictions automatically drive your future actions. Therefore, you have some freedom to hone your predictions in new directions, and you have some responsibility for the results. Not everyone has broad choices about what they can hone, but everyone has some choice.
This gets at a point I have made elsewhere; which is that we don’t necessarily need to think differently in order to act differently. By first changing our behaviour, we can affect our future thoughts.
Now, when I say responsibility, I’m not saying people are to blame for the tragedies in their lives or the hardships they experience as a result. We can’t choose everything that we’re exposed to. I’m also not saying that people with depression, anxiety, or other serious illnesses are to blame for their suffering. I’m saying something else: Sometimes we’re responsible for things not because they’re our fault, but because we’re the only ones who can change them. (emphasis added)
Since I commented on Barrett’s portrayal of psychiatric diagnoses as ‘illnesses’ above, we can skip over it here. I thought this excerpt was worth including, anyway, because it is a reminder to remove blame from the equation. Yes, bad things have happened. Perhaps, even terrible things. And you were probably not responsible for them. But who can forge a path forward now? Is it the people who harmed you in the past? Or is it the present day you?
Human Mind Defined
There is plenty more to learn from Seven and a Half Lessons About the Brain. For now, I leave you with Barrett’s answer to the question, What is a human mind?:
A mind is something that emerges from a transaction between your brain and your body while they are surrounded by other brains-in-bodies that are immersed in a physical world and constructing a social world.
