Behave: The Biology of Humans at our Best and Worst

Robert M. Sapolsky. Penguin, 2017. 790 pages. $35.00.

Winner of the 2018 Phi Beta Kappa Award in Science

By Douglas Keith Candland

The question “Are human beings guided by their best or worst angels?” has become a prominent one in the mind of the public psyche. The question lurks in every aspect of social science. An answer, often tacit, is unavoidable in the practice of everyday life, for it is the perennial question of What is nature? What is nurture? Tucked away in any complete answer is the additional question as to whether nature and nurture are by themselves fixed or variable, ‘good’ or ‘bad’. The answer we select determines our politics, our religious views, our mating and child-rearing practices, and how we distinguish good from evil, ignorance from wisdom. In contemporary thought, the answer requires attention to our human neurology, perhaps not as the sole determiner of behavior, but as a modifiable partner with environment and culture.

During the last few decades, neuroscience has been the growth industry of the academies, wherein researchers from previously differing fields have found common cause. Impetus and sustenance have come from technology, specifically the inventions of ways to assess activity of the structures of the central nervous system. As recently as the 19th century, knowledge of the function of different areas of the human brain was largely based on the accidental fruits of war when injuries to the brain were examined in relation to changes in behavior. The remarkable story of Phineas Gage, whose temperament changed to the intolerable after a steel rod blasted through half his brain is retold by Robert M. Sapolsky within the book here reviewed, along with hundreds of other tales, observations, and experiments, all concerned at varying levels with the relationship between brain and behavior.

Sapolsky’s goal is to offer a wide-ranging and vigorous accounting of our current understanding of how the brain leads to behavior (and behavior to the structure of the brain), a task which is performed with the spirit, inclusiveness, and jokes of a first-rate university lecturer on what has come to be called neuroscience. Sapolsky stands firm: the relationship between brain and behavior is an intricate tautology with each altering the other. 

Today, each day brings forth reports of experiments and observations regarding how the brain and behavior relate. Sapolsky offers us descriptions and insights galore, aided by the judicious order of presentation. Chapter 1 elegantly reminds us that we denigrate our understanding of ourselves when we think of ‘science’ as existing at any one level. Any behavior can be investigated at the levels of genetics, epigenetics, physiology, motor patterns, gross behavior, and, demonstrations conducted by social and cognitive psychology. No one approach offers a full explanation. As evidence for this view of science, the book considers all of these approaches in commendable depth.

The reader hooked by the opening chapter is offered the chance to be current by fast-forwarding to Appendix 1, a refresher course on neurons. This reading is fruitful for understanding most of the text. There are two other appendices, one on neuroendocrinology and one on proteins. I shall suggest yet another, this on the methods now used to measure cranial and bodily activity, such as various brain imaging.

For the next third of the book, the author treats us to a clever organization based both on ontogeny and phylogeny, from what the brain is doing one second before behavior to how that particular connection evolved on human primates over huge periods of unrecorded time from prenatal, through infancy, childhood, adolescence, the normal and the unusual human mind. Readerwho do not keep bundles of scientific journals for bed-time reading will be astonished and invigorated by several accounts of newer ways of thinking, such as that ‘genes don’t mean much’ by which is meant that genes are ‘only’ the actors for which the drama of behavior is written. Or, as the author cogently writes “. . .it’s not meaningful to ask what a gene does, just what it does in a particular environment.”

Having been cleverly, thoroughly, and successfully informed on the ontogeny and phylogeny of genetic importance, the book takes a very sharp, perhaps dangerous tack. Here the reader travels, via the studies and ideas of social, cognitive, evolutional psychology, and sociology, toward modern life.  The chapters do so by presenting and evaluating anthropological/sociological/archeological discoveries and demonstrations relating, for example, the remnants of ancient bodies scared by war to the type of society (tight vs. loose; nomad vs. urban) highlighted by the author’s presentations and critiques. The critique section is especially strong in helping the reader to assess validity among the ideas of those who see in human beings better angels as opposed to those who are genetic pessimists.

Among the many values of the book are clear and straightforward explanations that may seem to be but academic warfare when, in fact, they are nuanced explanations of such matters as adaptation, kin-selection, punctuated equilibrium, and the continuing argument regarding whether it is useful to explain phylogeny in terms of social selection. The engaged and patient reader will come to see that while ‘evolution’ is not a pattern to be dismissed, neither is its complexity to be ignored. 

The remaining two-thirds of the book tack into dangerous winds that lead the reader to exciting intellectual landscapes. Among these are viewpoints on such matters as obedience, morality, empathy, the language of metaphor as killers, the criminal justice system, and, of course, free will. The support for the various views expressed are invariably and necessarily summaries of the one-shot demonstrations, passing as experiments. 

These demonstrations have in common little opportunity to measure repeatability as they describe unique happenings. Many show a lack of consideration of alternative conclusions whose possibility needs, but is not, tested by appropriate control studies. Some few are tied to neurology by correlational, not causal, measures of anatomical and physiological activation. 

In an Epilogue, the author lists thirty take-away conclusions, some specific, some very general. The chief take-away refers to the complicated interactions among genes, the environment, now and past, and behavior. The author wisely offers a glossary of 66 abbreviations used; e.g., v1PFC us the ventrolateral prefrontal cortex while vmPFC is ventromedial PFC 54. Reading the informative and witty footnotes is worthwhile.

The term ‘activation’ is used throughout the book as the measure of neural correlates to behavior. A thoughtful reader will wonder how activation is measured, how reliable such measures are upon repeated testing, the meaning of variability, the choice of subjects, and the likely generality of the results. To ask the author to consider these matters for each of the demonstrations cited is to ask the author to write a book he did not write. Nonetheless, as we have instructive appendices on other technical subjects, the readers’ ability to judge the author’s speculations would be aided by an appendix on how neuroscience measures activation so as to know what activation means and represents. 

We think that current technologies represent accurate measures of brain and behavior. Before definitive conclusions regarding society, justice, and life vs. death are made through these technologies, it would be wise to attend to their methodological epistemologies so as to understand their variability and reliability. 

Attempts to relate brain anatomy to temperament, emotions, talents, and behavior are many, expressed, as by the ancient Greeks as the four humors, by contemporaries as tests of personality, and, not so long ago as history goes, by phrenology. When Walt Whitman, then a reporter for the Brooklyn Eagle, visited ‘Professor’ O. S. Fowler’s ‘Phrenological Cabinet’, he traveled to lower Manhattan where customers could be informed of aspects of their personality by an examination of the shape of their skull. 

The Cabinet was said to be the second most visited property in New York City, the number of visitors ranking right behind Mr. Barnum’s Museum of Oddities. Perhaps Whitman was interested in knowing the degree of his degree of spirituality or amativeness. Phrenology got a bad rap over the last two century, perhaps because it became a vast commercial enterprise conducted at county fairs by the trained and untrained alike. In its earliest manifestations in the 1830s, it had a respectable empirical base. The validity of the measures—whether phrenology reliably measured temperament and behavior—was never assessed experimentally. 

Knowledge of how the brain relates to behavior has experienced a fruitful two centuries since phrenology ruled, mostly because we now have measures of activation and images of changes within the brain. As foolish as phrenology may seem to the modern reader, its success still provides a warning. When one reads a sentence in Sapolsky’s work such as ” . . .among male rhesus monkeys a large prefrontal cortex goes hand in hand with social dominance.” One suspects that ‘Professor’ Fowler, Walt Whitman, and maybe even Lamarck would think themselves rediscovered.

As author Sapolsky suggests, perhaps the book’s subtitle should be “It’s complicated.”

Robert M. Sapolksy became a member of Phi Beta Kapp at Harvard College in 1977.

Douglas Keith Candland (ΦBK, Pomona College, 1956) is the editor of 
Review of General Psychology and the Homer P.Rainey Professor of Psychology and Animal Behavior, Emeritus at Bucknell University. Bucknell University is home to the Mu of Pennsylvania chapter of Phi Beta Kappa.