Behave: The Biology of Humans at Our Best and Worst

by Robert M. Sapolsky

As empathic pain increases, your own pain becomes your primary concern.

Disabling empathy.

In contrast, the more individuals can regulate their adverse empathic emotions, the more likely they are to act prosocially. Related to that, if a distressing, empathy-evoking circumstance increases your heart rate, you’re less likely to act prosocially than if it decreases it. Thus, one predictor of who actually acts is the ability to gain some detachment, to ride, rather than be submerged, by the wave of empathy.

Empathy

This may be the answer. As we will see in chapter 8, the brain is heavily influenced by genes. But from birth through young adulthood, the part of the human brain that most defines us is less a product of the genes with which you started life than of what life has thrown at you. Because it is the last to mature, by definition the frontal cortex is the brain region least constrained by genes and most sculpted by experience. This must be so, to be the supremely complex social species that we are. Ironically, it seems that the genetic program of human brain development has evolved to, as much as possible, free the frontal cortex from genes.

Nature nurture

This is so wrong—foolishly pick a poor family to be born into, and by kindergarten, the odds of your succeeding at life’s marshmallow tests are already stacked against you.34

Poverty

But part of the link reflects the corrosive effects of subordination in all hierarchical species. For example, having a low-ranking mother predicts elevated glucocorticoids in adulthood in baboons.

Poverty

Thus, childhood adversity can atrophy and blunt the functioning of the hippocampus and frontal cortex. But it’s the opposite in the amygdala—lots of adversity and the amygdala becomes larger and hyperreactive.

Amygda.a

Childhood adversity accelerates amygdaloid maturation in a particular way. Normally, around adolescence the frontal cortex gains the ability to inhibit the amygdala, saying, “I wouldn’t do this if I were you.” But after childhood adversity, the amygdala develops the ability to inhibit the frontal cortex, saying, “I’m doing this and just try to stop me.”

Amygdala childhood adversity

Cultural tightness was also predicted by environmental degradation—less available farmland or clean water, more pollution. Similarly, habitat degradation and depletion of animal populations worsens conflict in cultures dependent on bush meat. And a major theme of Jared Diamond’s magisterial Collapse: How Societies Choose to Fail or Succeed is how environmental degradation explains the violent collapse of many civilizations.

Environmental degradation and societal collapse

This raises the key issue of what global warming will do to our best and worst behaviors. There will definitely be some upsides. Some regions will have longer growing seasons, increasing the food supply and reducing tensions. Some people will eschew conflict, being preoccupied with saving their homes from the encroaching ocean or growing pineapples in the Arctic. But amid squabbling about the details in predictive models, the consensus is that global warming won’t do good things to global conflict. For starters, warmer temperatures rile people up—in cities during the summers, for every three degree increase in temperature, there was a 4 percent increase in interpersonal violence and 14 percent in group violence. But global warming’s bad news is more global—desertification, loss of arable land due to rising seas, more droughts. One influential meta-analysis projected 16 percent and 50 percent increases in interpersonal and group violence, respectively, in some regions by 2050.53

Climate crisis = more war and violence.

most of earth’s humans have inherited their beliefs about the nature of birth and death and everything in between and thereafter from preliterate Middle Eastern pastoralists.

Abramic religion

regions. Those with the most interest in prestige and power seem least likely to feel for those less fortunate.23

Status and empathy

When humans invented material inequality, they came up with a way of subjugating the low ranking like nothing ever before seen in the primate world.

Inequality

reading problems of a type that we now call dyslexia aren’t due to laziness but instead involve microscopic cortical malformations. Twenty-five since we learned that epigenetics alters behavior.

Dyslexia