Behave: The Biology of Humans at Our Best and Worst

by Robert M. Sapolsky

First, no part of the adult brain is more shaped by adolescence than the frontal cortex. Second, nothing about adolescence can be understood outside the context of delayed frontocortical maturation. If by adolescence limbic, autonomic, and endocrine systems are going full blast while the frontal cortex is still working out the assembly instructions, we’ve just explained why adolescents are so frustrating, great, asinine, impulsive, inspiring, destructive, self-destructive, selfless, selfish, impossible, and world changing.

A cloud may be less tangible than a brick, but it’s constructed with the same rules about how atoms interact.

Eat your vegetables, floss your teeth, remember to say, “It’s difficult to quantitatively assess the relative contributions of genes and environment to a particular trait when they interact.”

This suggests a radical conclusion: it’s not meaningful to ask what a gene does, just what it does in a particular environment.

Repeat the mantra: don’t ask what a gene does; ask what it does in a particular context.

A final depressing point about inequality and violence. As we’ve seen, a rat being shocked activates a stress response. But a rat being shocked who can then bite the hell out of another rat has less of a stress response. Likewise with baboons—if you are low ranking, a reliable way to reduce glucocorticoid secretion is to displace aggression onto those even lower in the pecking order. It’s something similar here—despite the conservative nightmare of class warfare, of the poor rising up to slaughter the wealthy, when inequality fuels violence, it is mostly the poor preying on the poor.

Agriculture makes people dependent on a few domesticated crops and animals instead of hundreds of wild food sources, creating vulnerability to droughts and blights and zoonotic diseases. Agriculture makes for sedentary living, leading humans to do something that no primate with a concern for hygiene and public health would ever do, namely living in close proximity to their feces. Agriculture makes for surplus and thus almost inevitably the unequal distribution of surplus, generating socioeconomic status differences that dwarf anything that other primates cook up with their hierarchies.

Hamilton showed that eusocial insects’ unique genetic system makes a colony of ants, bees, or termites a single superorganism; asking why worker ants forgo reproduction is like asking why your nose cells forgo reproduction.

Dawkins introduced a great metaphor: a cake recipe is a genotype, and how the cake tastes is the phenotype.* Genotype chauvinists emphasize that the recipe is what is passed on, the sequence of words that make for a stable replicator. But people select for taste, not recipe, say the phenotypists, and taste reflects more than just the recipe—after all, there are recipe/environment interactions where bakers differ in their skill levels, cakes bake differently at various altitudes, etc. The recipe-versus-taste question can be framed practically: Your cake company isn’t selling enough cakes. Do you change the recipe or the baker?

Starting with Theodor Adorno in the 1950s, people have suggested that lower intelligence predicts adherence to conservative ideology.

In other words, conservatives start gut and stay gut; liberals go from gut to head.34

Linda Skitka of the University of Illinois emphasizes how the personal attributions of snap judgments readily feel dissonant to liberals, at odds with their principles; thus they are motivated to think their way to a more consonant view. In contrast, even with more time, conservatives don’t become more situational, because there’s no dissonance.

The differing views of novelty certainly explain the liberal view that with correct reforms, our best days are ahead of us in a novel future, whereas conservatives view our best days as behind us, in familiar circumstances that should be returned to, to make things great again.

Exploring the differences in neurobiology between liberals and conservatives, this quote really stuck with me for some (obvious) reason.

One study inspired by Milgram was the Hofling hospital experiment, in which nurses, unaware that they were in an experiment, would be ordered by an unknown doctor to give a dangerously high dose of a medication to a patient. Despite their knowing of the danger, twenty-one out of twenty-two nurses were willing to comply.