{"id":69655,"date":"2022-06-20T10:49:00","date_gmt":"2022-06-20T14:49:00","guid":{"rendered":"https:\/\/www.shortform.com\/blog\/?p=69655"},"modified":"2022-06-29T09:04:53","modified_gmt":"2022-06-29T13:04:53","slug":"behave-sapolsky","status":"publish","type":"post","link":"https:\/\/www.shortform.com\/blog\/behave-sapolsky\/","title":{"rendered":"Behave by Robert Sapolsky: Book Overview"},"content":{"rendered":"\n

What is Robert Sapolsky’s Behave<\/em> about? What is the key message to take away from the book? <\/p>\n\n\n\n

Understanding people is crucial to disciplines and careers ranging from psychology to sales. While there are countless books about how to relate to people\u2014and sometimes how to manipulate them\u2014few try to get to the core of human behavior in the same way that Sapolsky’s Behave: The Biology of Humans at Our Best and Worst <\/em>does.<\/p>\n\n\n\n

Below is a brief overview of the key themes. <\/p>\n\n\n\n\n\n\n\n

Nature: Biology and Genetics<\/strong><\/h2>\n\n\n\n

We\u2019ll start by examining the \u201cnatural\u201d causes of behavior: that is, biology and evolution. First, we\u2019ll discuss the structure of the brain<\/a> and some of its major functions, then we\u2019ll move on to how hormones influence what we do, and finally we\u2019ll look at some behavioral patterns<\/a> that have been encoded in us through countless generations of evolution.<\/p>\n\n\n\n

In Behave<\/em>, Sapolsky argues that the nature part of the nature versus nurture debate has less impact than many people believe.<\/p>\n\n\n\n

(Shortform note: Many researchers today\u2014including Sapolsky\u2014no longer recognize a clear divide<\/a> between our genetics and our environments when it comes to behavior. Rather, as we\u2019ll see in this guide, just about everything is the result of interactions <\/em>between nature and nurture. In other words, there\u2019s no such thing as a gene that forces us to act a certain way. At most, one could say that genes predispose us to certain behaviors.)<\/p>\n\n\n\n

The Structure of the Brain<\/strong><\/h3>\n\n\n\n

While numerous things influence what we do, the brain is the command center of the body where the final decisions are made. Therefore, the brain\u2019s design and how it works is an ideal place to begin when discussing behavior. <\/strong><\/p>\n\n\n\n

The 3 Levels of the Brain<\/h4>\n\n\n\n

Sapolsky starts by explaining how the brain works<\/a> in very general terms. He explains that our thought processes operate in three different \u201clevels\u201d:<\/p>\n\n\n\n

1. Top level: neocortex. <\/strong>This is the most recently evolved part of the brain and a feature we share only with our closest animal relatives, the primates. The neocortex is associated with deep thought, reasoning, memory, and processing sensory information. Based on what you\u2019re thinking about, the neocortex sends signals down to the limbic system<\/a>.<\/p>\n\n\n\n

2. Middle level: limbic system. <\/strong>The limbic system is found in all types of mammals, meaning that it evolved earlier than the neocortex. The limbic system is associated with emotions; in more scientific terms, with positive and negative responses to stimuli. Based on those stimuli, the limbic system sends signals to the core regulatory functions.<\/p>\n\n\n\n

3. Base level: core regulatory functions. <\/strong>This section controls our most basic and instinctive processes\u2014the things you have little or no control over. For example, if the oxygen levels in your blood fall too low, the reptilian complex will signal you to start breathing more heavily, which is why you start panting when you\u2019re exercising.  <\/p>\n\n\n\n

(Shortform note: Some sources refer to the base level as the \u201creptilian complex\u201d<\/a> (which gives rise to the colloquial \u201clizard brain\u201d). However, Sapolsky doesn\u2019t use that term in Behave.<\/em>)<\/p>\n\n\n\n

Sapolsky adds that, in some cases, thought processes can skip the neocortex and (more rarely) the limbic system, generating much faster and more instinctive responses.<\/strong> <\/p>\n\n\n\n

For example, if you read a recipe, you might think it sounds delicious (neocortex), triggering a positive emotional response (limbic system), sparking feelings of hunger and causing you to salivate (reptilian complex). However, if you see or smell food, it would skip the reasoning step and jump right to the emotional response, followed by the physical one. If you\u2019re starving and your blood sugar is low, that signal would skip straight to the base reptilian complex of your brain and make you feel physically hungry\u2014no logic or emotion needed. <\/p>\n\n\n\n

The Amygdala: Fear and Aggression<\/h4>\n\n\n\n

The amygdala is part of the limbic system, the \u201cmiddle\u201d level of the brain, and controls our feelings of fear, anxiety, and aggression. <\/strong><\/p>\n\n\n\n

Sapolsky says that our brains will naturally organize people into two groups: \u201cus\u201d and \u201cothers\u201d (sometimes you might hear this as \u201cin-group\u201d and \u201cout-group\u201d). We feel positive emotions<\/a> (pride, empathy, love, and so on) toward people whom we\u2019ve determined are like us, and negative emotions (hatred, fear\u2014emotions controlled by the amygdala) toward those we\u2019ve decided are \u201cothers.\u201d<\/p>\n\n\n\n

Notably, the amygdala can activate much more quickly than the neocortex, meaning that our fear and hostility response to an \u201cother\u201d is automatic. <\/strong>The logic-based neocortex will then (hopefully) override that response. <\/p>\n\n\n\n

To illustrate the point, Sapolsky shares a study where subjects were shown images of people of different races while hooked to a brain scanner. People\u2019s amygdalas would activate upon seeing such an image for just one-tenth of a second\u2014too short a time for the subjects to even identify what they\u2019d just seen, or to consciously feel their response to it. If the image remained onscreen for longer, the frontal cortex would then kick in and soothe the aggressive response. <\/p>\n\n\n\n

The Frontal Cortex: Reasoning and Restraint<\/h4>\n\n\n\n

The frontal cortex is the part of the neocortex at the very front of the brain, and it\u2019s involved in reasoning, conscious decision-making<\/a>, and self-control. As such, Sapolsky says that the frontal cortex is, more than any other part of the brain, what shapes a person\u2019s personality and choices. In other words, the frontal cortex is what makes us who we are.<\/strong><\/p>\n\n\n\n

Sapolsky also says that the frontal cortex is the last part of the brain to finish developing\u2014in fact, it\u2019s not considered fully developed until a person\u2019s mid-20s. Furthermore, the frontal cortex is shaped by experiences much more so than by genes. These facts have profound implications for the \u201cnature versus nurture\u201d debate: Sapolsky argues that a person\u2019s upbringing has a much greater impact on his or her character than genetics do. <\/strong><\/p>\n\n\n\n

(Shortform note: From adolescence to our mid-20s, countless variables impact how the frontal cortex develops. Since, as Sapolsky says, the frontal cortex is crucial to our decision-making processes, that means that everything from the food we eat, to the air quality where we grow up<\/a>, to how much sleep we get has a significant impact on who we eventually become.)<\/p>\n\n\n\n

Neuroplasticity: Changes in Brain Structure<\/h4>\n\n\n\n

For all the common talk of nature versus nurture, Sapolsky tells us that nurture can have real and significant impacts on our biology\u2014our nature. For one thing, the brain\u2019s physical structure can change to adapt to various circumstances and stresses.<\/strong> For example, an artist\u2019s brain might have a significantly larger cerebellum than normal (the cerebellum is associated with visualization and fine motor skills). In a sense, your brain behaves like your muscles: The parts you use the most become bigger and stronger. <\/p>\n\n\n\n

Furthermore, these physiological changes to the brain can have significant impacts on our behavior. <\/strong>A naturally thoughtful person might develop a stronger neocortex and become even more thoughtful and rational, while an impulsive and emotional person could go in the opposite direction and become even more emotionally driven. <\/p>\n\n\n\n

However, the opposite holds true as well: With sustained effort, we can train our brains to strengthen character traits we like and weaken traits we don\u2019t like. As Sapolsky says more than once, environment and experience have greater impacts on our behavior than biology. <\/p>\n\n\n\n

Hormones: The Body\u2019s Messengers<\/strong><\/h3>\n\n\n\n

While the brain ultimately decides what we\u2019ll do, making those decisions requires input from the entire body.<\/strong> A great deal of that input relies on, or is influenced by,  hormones<\/em>\u2014chemicals that initiate and regulate various functions.<\/p>\n\n\n\n

There are dozens of hormones at work within the human body, but Sapolsky focuses on the ones that are especially relevant to behavior\u2014specifically, dopamine, serotonin, oxytocin, and testosterone.<\/p>\n\n\n\n

Dopamine and Serotonin: Motivation Molecules<\/h4>\n\n\n\n

Dopamine is a neurotransmitter that promotes goal-oriented actions; think of it as the \u201cmotivation hormone.\u201d<\/strong> Interestingly, Sapolsky says that dopamine is more about the anticipation <\/em>of a reward than about enjoying the reward itself\u2014in other words, we get dopamine boosts when we work toward a goal, not just when we achieve it. <\/p>\n\n\n\n

Serotonin is another neurotransmitter associated with happiness and motivation. Sapolsky says that serotonin works in conjunction with dopamine to enhance its effects, particularly when it comes to long-term goals. Low serotonin is linked with impulsiveness, aggression, and antisocial behavior\u2014though, strangely, high <\/em>serotonin levels have been found to have the same effects. As with everything about human behavior, Sapolsky says that serotonin\u2019s exact effects depend on numerous other variables, and even the scientists running the studies can\u2019t always say what those variables are.<\/strong><\/p>\n\n\n\n

(Shortform note: Deficiencies in dopamine and serotonin are believed to cause various mental health disorders. For example, some researchers believe that a lack of dopamine causes\u2014or at least contributes to\u2014Attention Deficit Hyperactivity Disorder (ADHD)<\/a>. The dopamine deficiency causes people with ADHD to quickly lose focus on goals<\/a>, and they have difficulty with emotional regulation. Similarly, many doctors believe that a serotonin deficiency contributes to depression<\/a>.)<\/p>\n\n\n\n

Oxytocin: The \u201cLove Drug\u201d<\/h4>\n\n\n\n

Oxytocin (and the closely related hormone vasopressin) reduces aggression, increases empathy and trust<\/a>, and promotes bonding behaviors like physical touch or eye contact. In short, oxytocin and vasopressin cause us to act in a more prosocial <\/em>way\u2014that is, in ways that are supportive and helpful to others. Furthermore, experiencing prosocial behavior causes us to produce more oxytocin, creating a positive feedback loop.<\/p>\n\n\n\n

However, Sapolsky warns that the apparently-positive effects of these hormones greatly depend on context: While oxytocin and vasopressin make us more helpful to people in our in-group, they actually make us more aggressive and suspicious toward those who aren\u2019t.<\/strong> In other words, they strengthen the bonds we already have, but also make us more insular and hostile toward outsiders. <\/p>\n\n\n\n

(Shortform note: In addition to making us more aggressive toward \u201coutsiders,\u201d oxytocin can also make us more forgetful<\/a>. However, oxytocin\u2019s effects on memory\u2014like so many things Sapolsky discusses\u2014seem to be context-dependent. Briefly, the researchers found that people who are more comfortable relying on others scored worse on a memory test after taking oxytocin, while more independent people actually scored better<\/em> after taking it. The researchers concluded that more study was needed to determine exactly how oxytocin affects memory, and how it interacts with people\u2019s tendencies toward independence<\/a>.)<\/p>\n\n\n\n

Testosterone: Impulsiveness and Confidence<\/h4>\n\n\n\n

Testosterone increases self-assurance and optimism while decreasing anxiety. It also suppresses part of the neocortex while boosting limbic system activity\u2014in short, it makes you more impulsive and less rational. <\/p>\n\n\n\n

Sapolsky says that many people think testosterone causes aggression. However, while there is a correlation between testosterone and aggression, it\u2019s not as strong nor as direct as previously thought. In fact, if anything, it appears to be the other way around: Aggressive behavior leads to testosterone production, rather than high testosterone levels leading to aggressive behavior.<\/strong>  <\/p>\n\n\n\n

(Shortform note: As people age\u2014especially men\u2014reduced testosterone levels<\/a> can cause physical and emotional changes. Most notably, people may experience decreased bone and muscle strength, as well as a loss of motivation and a generally depressed mood. Doctors have found that testosterone therapy can reverse some of these effects in aging men. Some men have reported feeling younger and stronger after taking testosterone supplements, but there\u2019s little scientific evidence supporting it as a treatment for those with normal testosterone levels for their age.) <\/p>\n\n\n\n

Evolved Behaviors<\/strong><\/h3>\n\n\n\n

Our brains and hormones\u2014and all of the \u201cnatural\u201d effects on our behaviors\u2014work the way they do because of evolution: <\/strong>Ancestors who behaved in certain ways were more likely to survive and reproduce, passing on the genes that caused them to behave in those ways. So now, many generations later, those genes still survive in us and influence our behavior.<\/p>\n\n\n\n

Let\u2019s examine a few broad categories of human behavior closely related to survival and reproduction. <\/p>\n\n\n\n

(Shortform note: In The Selfish Gene<\/em><\/a>, Richard Dawkins makes the case that human behaviors are becoming less genetically driven as we continue to evolve.<\/strong> In particular, he believes that our advanced brains\u2014our consciousness\u2014give us the ability to go against our genetically programmed instructions<\/a>. For example, our genes should compel us to have as many children as we can feasibly raise, but many people choose not to reproduce at all. However, even Dawkins doesn\u2019t think we\u2019ll ever be totally free of genetic imperatives; if nothing else, we\u2019ll always be driven to keep ourselves alive.)<\/p>\n\n\n\n

Kin Selection: Protecting Your Family<\/h4>\n\n\n\n

Kin selection<\/a> <\/em>is a term in evolutionary biology that means potentially sacrificing your own welfare or reproductive success in favor of your relatives\u2019\u2014for example, risking your life by fighting off a home intruder to protect your family. It evolved because, by definition, your relatives share many of your genes, so keeping them alive helps pass those genes on.<\/p>\n\n\n\n

Sapolsky says that kin selection explains a great number of human behaviors, but that we can also find countless examples of people going against what kin selection should dictate. For instance, we can read news articles about people killing family members, or millionaires donating incredible amounts of money to strangers. <\/p>\n\n\n\n

Sapolsky\u2019s theory is that humans <\/strong>do <\/em><\/strong>follow kin selection, but the way we decide who our \u201ckin\u201d are isn\u2019t entirely rational.<\/strong> On the one hand, we can look at total strangers and find similarities to ourselves. On the other hand, we can reject even our closest family members if they, for instance, behave in ways we find unacceptable. <\/p>\n\n\n\n

Furthermore, we can be manipulated into feeling more or less related to others. Propaganda can paint groups of people as dangerous and monstrous\u2014barely even human, let alone kin. And, conversely, campaigns emphasizing people\u2019s humanity and similarities to us have been crucial in everything from promoting LGBTQ+ rights to raising funds for cancer research. <\/p>\n\n\n\n

Reciprocal Altruism: Helping Each Other<\/h4>\n\n\n\n

A related phenomenon (no pun intended) is reciprocal altruism<\/a><\/em>\u2014the theory that it\u2019s often advantageous for unrelated individuals to work together. To give a common example, grooming behavior is common among animals that live in groups\u2014any member of the group will groom any other member, because making sure nobody\u2019s carrying fleas or ticks benefits the whole group.<\/p>\n\n\n\n

Sapolsky says that human society was founded on reciprocal altruism. <\/strong>Hunter-gatherer societies<\/a>, the earliest known type of human civilization, relied heavily on nonrelatives working together to keep everyone safe and fed. Therefore, reciprocal altruism is in our genes at least as strongly as kin selection is. <\/p>\n\n\n\n

Empathy and Compassion<\/h4>\n\n\n\n

Finally, empathy (echoing another person\u2019s feelings) and compassion (acting to improve another person\u2019s situation) have their place in our behaviors. <\/strong><\/p>\n\n\n\n

On the surface, empathy and compassion don\u2019t seem to follow the same kind of evolutionary logic as kin selection or reciprocal altruism\u2014we don\u2019t seem to benefit from sharing another\u2019s pain, or from acting to alleviate it. However, Sapolsky says that compassionate acts can (and usually do) have selfish aspects to them: A boost to our reputation, a sense of pride in our actions, or just the pleasant rush of dopamine that comes from doing a good deed. <\/p>\n\n\n\n

It\u2019s still not totally clear how empathy and compassion evolved, but it seems obvious that helping others is somehow advantageous. One theory Sapolsky favors is that empathy and compassion go hand-in-hand with our evolving brains and cultures: As we get better at reasoning and rational thought<\/a>, we realize more and more that helping strangers<\/a> benefits all of us.<\/strong> <\/p>\n\n\n\n

(Shortform note: As a partial counterpoint to Sapolsky, many animals show signs of empathy and compassion<\/a> toward one another. It\u2019s likely that our evolving brains made us better able to rationalize those feelings, and perhaps to foster them where they wouldn\u2019t otherwise exist, but it\u2019s misleading to say that only species with highly developed brains display empathy.) <\/p>\n\n\n\n

Nurture: Culture, Family, Environment, and Stimuli<\/strong><\/h3>\n\n\n\n

While biology explains internal influences on human behavior, Sapolsky says that external <\/em>influences\u2014including how we\u2019re raised, where we are at a given moment, and what\u2019s happening around us\u2014are even more important in determining how we act.<\/p>\n\n\n\n

Culture: How We\u2019re Raised<\/strong><\/h4>\n\n\n\n

Humans, like many other animals, instinctively want to fit in. We want to be part of the in-group, so we obey our culture\u2019s rules, follow its beliefs, and expect others to do the same.<\/strong> Realizing that we\u2019re not matching the people around us can cause serious anxiety\u2014just imagine showing up to a fancy party in jeans and a t-shirt.<\/p>\n\n\n\n

Interestingly, studies show that our most deeply held values aren\u2019t things that we consciously think about following. For example, someone who\u2019s been raised to be honest doesn\u2019t decide <\/em>to tell the truth<\/a> or overcome the temptation to lie; that temptation never arises in the first place. In other words, you\u2019ll reflexively follow whatever core values<\/a> you were raised with, unless you make an active effort to do otherwise. <\/strong><\/p>\n\n\n\n

Religion: What We Believe<\/h4>\n\n\n\n

Throughout history, one of the most influential parts of a person\u2019s upbringing has been his or her religion. Sapolsky says that all religions share a few traits in common, which makes them ideal for understanding cultural effects on behavior:<\/p>\n\n\n\n