Max's Reviews > Behave: The Biology of Humans at Our Best and Worst

Sapolsky explores the causes of human behavior at every level. Although he throws in some zingers and catchy vernacular, this is a serious work that can read like a textbook. He divides the book in two parts. The first deals with everything that affects behavior: The brain, neurons, neurotransmitters, hormones; environmental factors particularly in adolescence, childhood, and the womb; culture, genes and epigenetics. The second half shows how all these factors combine to affect us as individuals and as a society. We are presented with an intricate array of influences and as often is the case, the more you know, the less clarity you have about what it all means.

In a particularly dense beginning (with appendices for the underlying science) we get primers on the brain and neurons, their structure and how they work. We see how the interplay of their many component parts modulates behavior leading to impulsiveness or restraint. In addition we learn how we are influenced by the way we produce and process neurotransmitters (dopamine, serotonin) and of course hormones (testosterone, oxytocin). Sapolsky shows that the effects of these chemicals are not as straightforward as commonly presented. For example, oxytocin, the widely heralded pair-bonding hormone, causes us to draw closer to family but also to be more distant to strangers, in effect, amplifying the “Us Versus Them” syndrome.

Sapolsky discusses a variety of factors that affect brain, emotional and cognitive development. He points out that the child facing poverty or abuse, lack of maternal interest or care, or lack of stimulation in the environment will be severely compromised. He focuses on adolescence. This awkward age is characterized by a fully developed limbic system which fosters emotions and a far from developed frontal cortex which supports reason. We all have witnessed the result. And of course there are genes which greatly affect behavior, but in context. Environmental effects shaping genes begin in the womb and continue through childhood. Epigenetic factors turn genes on or off. When genes are expressed their impact varies based on the other genes in play and the specific circumstances. For example the extensively studied 7R variant of the DRD4 gene makes you more generous than average if you grew up in a secure environment and less generous than average if you grew up in an insecure one. Sapolsky highlights other genes that cut both ways depending on environment.

But much more than brain structure, neurons, neurotransmitters, hormones and genes determine behavior. Our decisions and actions, often unconsciously, are affected by unrelated events occurring at the same time. People holding a cold glass of water in one hand will view others as colder than they otherwise would. If a reviewer reads your resume attached to a heavy clipboard, you are more likely to be judged more serious than others whose resumes are read on light clipboards. Subliminal images also impact our conscious perceptions. Sapolsky offers many examples of how our behavior is primed by sensorial input that does not enter our consciousness.

Cultural context is also important. What we expect to see affects what we will. This underlies much of the racism that is so divisive. Culture affects how we process what we see. Sapolsky points to the different ways people in collectivist cultures (East Asian) and individualist cultures (Western) focus their vision. Take a landscape photo with a person in the center. Someone from China will likely focus on the background as much or more than the person, an American just the reverse. Chinese immigrants to the US will take a generation to adopt the US priority in focusing on images.

How much of our behavior with respect to violence is due to human nature? Were prehistoric hunter gatherer societies more or less violent or warlike than we are today? Sapolsky reviews expert opinions on both sides of the argument. What a contrast between his excellent presentation of this issue and Harari’s one-sided presentation in Sapiens. We learn that experts disagree. However Sapolsky still echoes Harari, calling the agricultural revolution “one of the all-time human blunders”. I don’t understand this. Without the agricultural revolution Sapolsky would be digging roots or chasing antelopes if he was lucky enough to have ever been born. Instead he is exploring the depths of the human mind, increasing our understanding of who we are. No matter how idyllic you paint primitive existence, I could not value it over one where we can develop our minds and build a better future for our children, as hard as that may be.

In the second half of the book Sapolsky explores how all the forces that impact human behavior come together to influence the way we see each other and the world. He starts with a quote attributed to Robert Benchley, “There are two kinds of people in the world: those who divide the world into two kinds of people and those who don’t.” Sapolsky’s ensuing discussion of “Us Versus Them” is amazingly relevant to the current political dialogue in the U.S. Our political proclivity to be liberal or conservative is 50% heritable. Each position embodies a larger set of beliefs. Conservatives most highly value loyalty, authority and sanctity while liberals most highly value care, fairness and liberty. One study gave another reason why our political choices are less than rational. Groups of five-year-olds were asked to choose a captain for a boat ride to Candyland. Each group was asked to decide between pictures of two candidates. The pictures were from political contests across the US. The kids’ pick was the winner of the political contest 71% of the time.

How are moral choices made? Of course Sapolsky cites myriad influences. Particularly interesting is empathy. We tend to conflate this with compassion, but empathy often is an end in itself and precludes a compassionate act. Sapolsky points out that empathy may have evolved to help us learn. It’s one thing to learn first-hand that a hot iron burns, seeing what happens to someone else touching the iron is a better way to learn and the lessen is strongly reinforced if we actually feel the other person’s pain. This is probably why that part of the brain (anterior cingulate cortex) that processes empathy developed. Interestingly most people who perform heroic selfless acts don’t think or feel anything first, they act instantaneously.

Is there free will? Endlessly arguable, but if there is it certainly seems relegated to the back seat. Sapolsky explores what this implies for the American legal justice system. He believes we should abolish it in its present form. This doesn’t mean he thinks criminals should run free, but justice as punishment for an evil act makes no more sense than punishing an unreliable car. For everyone’s protection unsafe cars and dangerous criminals shouldn’t be allowed on the streets. Deterrence and public safety are legitimate reasons to lock people up, but not retribution. Capital punishment is clearly wrong.

Are times more peaceful than in the past? Sapolsky references Steven Pinker’s Better Angels of Our Nature, which now I will have to read. Perhaps violence is down as a percentage of population. In that respect one could say modern wars kill fewer people than ancient ones. However modern wars kill people faster. WWII killed 55 million people and at a faster rate than past major wars. Modern 21st century weapons are poised to kill us all in a flash. Are we at a lesser chance of war? Harari in Sapiens thinks so given the lack of a world war since the 1940’s. I’m reminded of Max Hastings in Catastrophe 1914 quoting an 80 year old Brit just before WWI. He assured his interviewer that there wouldn’t be a major war since in his experience these things always worked themselves out. Unfortunately his experience wasn’t quite long enough. Religion has been responsible for countless wars and still underlies much of the conflict today. Sapolsky brings up a quote I loved regarding religious wars. “People are fighting over who has the better imaginary friend.” attributed to Napoleon. Sadly, nationalistic populism is on the rise often citing religious values and demonizing “Them.”

All in all this is a great book if somewhat depressing. How much do we really control our own actions? The influences on human behavior are so many, so intertwined, and so complex that making sense of it seems almost hopeless. Still there are important lessons we can learn just understanding that fact. We can forego the presumptiveness of intuitively knowing why people behave the way they do. We can see that just casting blame and calling others evil will get us nowhere. Sapolsky gives us a detailed and thoughtful mix of facts and his opinions, of which I have covered small slices. It is not a light read, but if you want to understand why we do the things we do, it is very worthwhile.