Behave: The Most Important Book You Will Ever Read

A Book Review: The Biology of Humans at Our Best and Worst by Robert M. Sapolsky

This is quite possibly the best book on the biology of human behavior. I’ve always liked Sapolsky and was excited to dig in, but it was even better than expected. The book is divided into a sort of “timeline” of what causes behavior. This is because generally, behavior is caused by many different things — upbringing, genes, neurotransmitters, hormones, and many others. And all of them “cause” behavior, and they are all working in unison. This layout is to emphasize that the casual chain of events is incredibly vast, and not specific to any given field. For example, in the first chapter is about “one second before”, and focused on neurobiology. It touches on the limbic system, amygdala, frontal cortex, dopamine system and serotonin. This provides a foundation for the rest of the book, with how the nervous system handles pro and antisocial behavior.

The book then moves to different chapters illustrating different “time-points” of the behavioral causal chain. From “one second before”, it follows by minutes before, then hours and days before and to days to months before. Next, it goes into the role of adolescence, the womb and fertilized egg. This part ends with “centuries and millennia before” and “the evolution of behavior”. The former focused on cultural evolution, and the latter on evolutionary psychology.

To this point, the book describes more or less the biology that causes behavior, even though it is only the first part of the book. The second half tries to be more practical and uses the information previously covered to make broader social, political and historical insights. It covers “us versus them”, hierarchy, morality, empathy, the justice system, war, and much more. The whole narrative is always pointed to moral action, either at the good or bad end, remaining true to its subtitle, “the biology of humans at our best and worse”.

Something that becomes impossible to ignore is the extreme nuance of everything related to both biology and behavior. For example, testosterone doesn’t have as strong of a link to aggression as you may think. Within the normal range, it cannot predict aggressive behavior, and it seems to function more as sensitivity to any type of triggering, especially in situations to maintain social status. In cases where status is associated with prosocial behavior, it has the opposite effect of aggression. On the other hand, while oxytocin increases pair-bonding and prosocial behavior, it does so only for the in-group, and the antisocial behavior towards outgroups increase, increasing ethnocentrism and xenophobia. This is just a droplet in the ocean of similar information that the book covers.

I find that this is a good buffer against political extremism. People on the far left which tend to view everything as socially constructed, are going to have a very significant shift in their worldview. And similarly, those on the far right who tend to emphasize biology so much will realize how biology is a lot more complicated than they think, and viewing biology in isolation without an environment is very reductivist and short-sighted.

The scope of the book is immense. I typically write some notes of information that is worth saving when reading a book. I try to minimize their amount to avoid having a gigantic list, and I usually make 5 to 10 notes per book. In this one, it was over 60. I read it many months ago before doing this review, and just thinking about it and going over the notes; I want to read it again. I was already familiar with almost every single topic the book covered, and yet I learned so much. While it at times gets technical, especially in the beginning, it is nevertheless very accessible as a whole.

If you’re interested in human behavior, this is not only a recommended read but a mandatory one. It is a bit long, but it is worth it. If you want to understand the world, you need to understand human beings. If you want to understand human beings, you need to understand their behavior. And if you want to understand human behavior, you need to learn its biological underpinnings. Read it.

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I also have a philosophy podcast. If you want to check it out look for Anagoge Podcast.

Tiago V.F.