Review: Robert M. Sapolsky’s “Behave”

by Miles Raymer


Books that examine the relationship between science and morality have become ubiquitous, so readers interested in these important subjects need to choose carefully. It is not an overstatement to say that one could do no better than to alight on Robert M. Sapolsky’s Behave. This engrossing, encyclopedic examination of the causal mechanisms that determine human behavior is a monumental achievement of syncretic thought.

This was my first journey into Sapolsky’s singular mind, both joyful and challenging. Covering an almost inconceivably vast landscape of scientific information, this neurobiologist/primatologist takes a playful but responsible approach to some heady topics, delving deep into humanity’s best and worst behaviors while never missing an opportunity to charm the reader with his perspicacious wit. I usually don’t care for comedy in nonfiction, but Sapolsky’s wry humor rarely misses the mark, and is complemented by an impressive ability to synthesize multiple perspectives and extricate sensible conclusions from dense and sometimes-conflicting data. Sapolsky is also transparent about his own biases as a “bleeding heart liberal,” making him a truly lovable genius (and not just in the casual sense).

Since it would be folly to try to cover everything this book has to offer in a review, I’ll focus on explaining Sapolsky’s methodology, and then comment on just a few of his most important findings. Sapolsky begins with a necessary critique of how scientists typically explain human behavior, which is to break it down into different “buckets of explanation,” each of which comprises a distinct realm of inquiry:

We tend to use a certain cognitive strategy when dealing with complex, multifaceted phenomena, in that we break down those separate facets into categories, into buckets of explanation…The goal of this book is to avoid such categorial thinking. Putting facts into nice cleanly demarcated buckets of explanation has its advantages––for example, it can help you remember facts better. But it can wreak havoc on your ability to think about those facts. This is because the boundaries between different categories are often arbitrary, but once some arbitrary boundary exists, we forget that it is arbitrary and get way too impressed with its importance…

There are not different disciplinary buckets. Instead, each one is the end product of all the biological influences that came before it and will influence all the factors that follow it. Thus, it is impossible to conclude that a behavior is caused by gene, hormone, childhood trauma, because the second you invoke one type of explanation, you are de facto invoking them all. No buckets. A “neurobiological” or “genetic” or “developmental” explanation for a behavior is just shorthand, an expository convenience for temporarily approaching the whole multifactorial arc from a particular perspective. (5-8, emphasis his)

This boundary-busting approach puts Sapolsky squarely in the company of intellectual titans such as Edward O. Wilson and Steven Pinker––interdisciplinary thinkers who have, however imperfectly, combined findings from numerous academics fields to launch humanity into new realms of inquiry and debate. Sapolsky is less poetic than Wilson and less contentious than Pinker, bringing a cautious, even-handed compassion to the science of understanding human nature. As any science reader knows, it is one thing to claim that disciplinary boundaries are arbitrary and ought to be ignored, and quite a different thing to actually demonstrate how this can be done. And while I don’t think Sapolsky fully achieves his stated goal, his efforts to do so are heroic and effectual.

The first half of Behave plays out like a tennis match that travels back in time, with the ball representing the focus of Sapolsky’s chapters and the net representing a (somewhat arbitrary) boundary between behavioral mechanisms that operate primarily inside or outside the human body. He begins with “One Second Before,” an explanation of the neurobiology that takes place just before behavior is enacted, then transitions to “Seconds to Minutes Before,” where he discusses immediate environmental stimuli that contribute to behavior. Next comes “Hours to Days Before,” a discussion of how hormones influence behavior, which is followed by “Days to Months Before,” where he takes up long-term neural plasticity (learning and memory).

This pattern continues, with subsequent chapters addressing adolescence, early childhood development, genetics, culture, and humanity’s shared evolutionary heritage. So Sapolsky makes use of the buckets of explanation by taking up these topics one at a time (what else could he do?), but also goes to great lengths to show as many interactive areas of overlap between the different causal mechanisms as possible. This truly is a “both/and” story he is telling, with all the moving parts affecting all the other moving parts in profound and intriguing ways.

The second half of Behave is more traditionally structured, and wades into dicier territory. Sapolsky tackles tricky subjects such as tribalism, moral intuition and bias, power dynamics, ethical motivation, empathy, the power of symbols to move us to action (or not), free will, criminal justice, and war. These areas of study are all rapidly evolving along with society and technology, so it’s impossible to tell how relevant Sapolsky’s assessments will be in decades to come. But all in all, this is the best and most up-to-date summary of recent findings in these fields one could hope to engage with. I probably had to read between ten and twenty other books to discover most of the insights Sapolsky distills into just a few hundred pages.

All of this should be more than enough to convince science and ethics enthusiasts that Behave is essential reading. If you’re eager to run out and pick it up, just stop reading here and go for it. But if you want to stick around, I’ll give some thoughts about what I see as Sapolsky’s most important findings.

Sapolsky’s most critical point by far is the importance of context in understanding human behavior. This is hardly a novel position, but Sapolsky lays out the argument for contextualization with sui generis assiduousness and clarity. Over and over he pounds the table about context, tirelessly illuminating the ways in which human behavior is sensitive to myriad influences both inside and outside the body. Most of these influences are partially or completely hidden from our conscious experience of the world, and it is only through scientific inquiry and abstraction that we come to understand their significance. Perhaps the wildest demonstration of this is the role of transcription factors in determining how a person’s genome expresses itself:

95 percent of DNA is noncoding…What is that 95 percent? Some is junk––remnants of pseudogenes inactivated by evolution. But buried in that are the keys to the kingdom, the instructional manual for when to transcribe particular genes, the on/off switches for gene transcription. A gene doesn’t “decide” when to be photocopied into RNA, to generate its protein. Instead before the start of the stretch of DNA coding for that gene is a short stretch called a promoter––the “on” switch. What turns the promoter switch on? Something called a transcription factor (TF) binds to the promoter…Thus transcription factors regulate genes. What regulates transcription factors? The answer devastates the concept of genetic determinism: the environment. (226, emphasis his)

Sapolsky goes on to explain that numerous factors––ones present inside cells, inside bodies, and even outside bodies––can all nudge transcription factors one way or another. This means that, while a person’s genome stays constant throughout life, gene expression (the manner in which genes code for the particular proteins that make you you) is keenly sensitive to environmental conditions and constantly in flux. Furthermore, it turns out that transcription factors are usually proteins themselves, and therefore require other transcription factors to instruct genes to code for them:

Genomes aren’t infinite; instead TFs regulate one another’s transcription, solving that pesky infinity problem. Importantly, across the species whose genomes have been sequenced, the longer the genome (i.e., roughly the more genes there are), the greater the percentage of genes coding for TFs. In other words, the more genomically complex the organism, the larger the percentage of the genome devoted to gene regulation by the environment...The human genome codes for about 1,500 different TFs, contains 4,000,000 TF-binding sites, and the average cell uses about 200,000 such sites to generate its distinctive gene-expression profile. This is boggling. (228-9, emphasis his)

Boggling indeed, but also fucking fabulous. O brave new world, that has such people in ‘t! 

The level of detail and complexity in the example above is indicative of every section and chapter Behave has to offer. Sapolsky doesn’t cut corners or succumb to simplistic reductionism, seeking instead to repeatedly blow the reader’s mind by showing the grand scope of what goes into decisions as simple as deciding whether to reach out to touch someone’s arm. Every step of the way, we are bombarded with caveats, clarifications, contradictions, and pitfalls of empirical limitation. It would be infuriating if it weren’t so damned fascinating! Sapolsky’s main thrust––that context is always crucial and never simple when trying to understand behavior––could not be better delivered. It also carries a hopeful undertone because many of the environmental contexts in which humans must operate are created and controlled by humans, implying that we can genuinely help people lead better lives if we learn how to fiddle the environmental dials the right way. Our power in this regard is far from limitless, but hardly insignificant (I’ll return to this at the end of the review).

Behave also contains strong arguments for the elimination of poverty and abuse, especially in the lives of children. Sapolsky grinds out a glut of ghastly facts about how “childhood adversity” can compromise people later in life:

Childhood adversity increases the odds of an adult having (a) depression, anxiety, and/or substance abuse; (b) impaired cognitive capacity, particularly related to frontocortical function; (c) impaired impulse control and emotion regulation; (d) antisocial behavior, including violence; and (e) relationships that replicate the adversities of childhood (e.g., staying with an abusive partner). (194)

He immediately follows up by pointing out that “some individuals endure miserable childhoods just fine,” and makes it clear that anything goes when looking at a particular case (194). But the trending effects of childhood adversity are undeniable and terrible. Like many other insights in Behave, this is not anything we didn’t already know; it’s the sheer volume and artful presentation of Sapolsky’s converging evidence that gives his work inimitable force. He is also not afraid to bind these findings to strong, empirically-based arguments that reject egregious income inequality and promote investment in public goods:

It’s not so much that poverty predicts poor heath; it’s poverty amid plenty––income inequality. The surest way to make someone feel poor is to rub their nose in what they don’t have…When social capital decreases (thanks to inequality), up goes psychological stress…If you want to improve health and quality of life for the average person in a society, you spend money on public goods––better public transit, safer streets, cleaner water, better public schools, universal health care…Inequality means more secession of the wealthy from contributing to the public good. (294-5)

There’s no denying that this is a kind of liberal do-gooder wishlist, tinged with Sapolsky’s political leanings. Although it leaves him open to criticism, I admire Sapolsky for linking research with certain normative outcomes when he deems it appropriate. It is a fitting strategy for this moment in time, when the notion of any truly “objective” source of information has become obsolete. The best we’ve got are people like Sapolsky, who humbly bend the knee to reason and reality even when they’d rather the universe were otherwise, and who also fight tooth and nail to be heard when reason and reality actually support their political points of view.

The final aspects of Behave I want to take up are Sapolsky’s direct claims that we can and should use science to improve the chances of people acting well instead of badly, along with his implicit argument that narrative and storytelling have a huge role to play in this grand project. While science is perhaps humanity’s most powerful method for analyzing and improving environmental conditions, narrative is a timeless tool for teaching people to assume the perspectives of others and to individuate potential enemies instead of reducing them to faceless members of a reviled out-group. This comes through in Sapolsky’s recommendations for dealing with humanity’s inescapably tribal nature:

From massive, breathtaking barbarity to countless pinpricks of microaggression, Us versus Them has produced oceans of pain. Yet our generic goal is not to “cure” us of Us/Them dichotomizing. It can’t be done…If we accept that there will always be sides, it’s a nontrivial to-do list item to always be on the side of angels. Distrust essentialism. Keep in mind that what seems like rationality is often just rationalization, playing catch-up with subterranean forces that we never suspect. Focus on the larger, shared goals. Practice perspective taking,. Individuate, individuate, individuate. Recall the historical lessons of how often the truly malignant Thems keep themselves hidden and make third parties the fall guy. (423-4)

Sapolsky doesn’t take what I see as the next logical step here, which is to assert that the easiest way people can begin checking off his anti-tribal “to-do list” is to engage with stories that open the way to novel perspectives and unfamiliar modes of moral calculus. We should draw heavily on the power of narrative to simulate social complexity and teach the lessons Sapolsky rightly identifies as essential for ethical education. He points out in a later chapter that, despite its considerable downsides, “our confusion of the literal and the metaphorical, our granting of life-threatening sanctity to the symbolic, can be used to bring about the best of our behaviors” (579). There is a momentous marriage between the arts and sciences embedded in this outlook––a marriage more sacred than any of the supposedly sacrosanct folderol that has hitherto spawned from the imaginative shit-heap of human history.

Stories can teach us to think and act better, but only science can deliver the building blocks and blueprints for our better world. When wrapping up a discussion of how former enemies reach reconciliation, Sapolsky implores readers to “recognize that science can teach us how to make events like these more likely” (670). He knows it’s a game of probability; we can’t force people to be good, but we can make it systemically easier for them to make the right choice, even if we know the “rightness” of that choice will always be at least partially if not wholly circumstantial. The more we learn about the light and dark tendencies inherent in human nature and particular arenas of action, the more capable we become of incentivizing instances of good behavior and minimizing instances of bad behavior. Scrupulousness of the highest order is called for, but the project is both worthy and necessary.

I’d be delighted to spin out some final words that would drive home everything that is special about this book, but I couldn’t hope to top Sapolsky himself:

If you had to boil this book down to a single phrase, it would be “It’s complicated.” Nothing seems to cause anything; instead everything just modulates something else. Scientists keep saying, “We used to think X, but now we realize that…” Fixing one thing often messes up ten more, as the law of unintended consequences reigns. On any big, important issue it seems like 51 percent of the scientific studies conclude one thing, and 49 percent conclude the opposite. And so on. Eventually it can seem hopeless that you can actually fix something, can make things better. But we have no choice but to try. And if you are reading this, you are probably ideally suited to do so. You’ve amply proven you have intellectual tenacity. You probably also have running water, a home, adequate calories, and low odds of festering with a bad parasitic disease. You probably don’t have to worry about Ebola virus, warlords, or being invisible in your world. And you’ve been educated. In other words, you’re one of the lucky humans. So try. (674-5)

Rating: 10/10