Book review: On Deep History and the Brain

On Deep History and the Brain, by Daniel Lord Smail
Berkeley: University of California Press, 2008

When did human history begin? Most general histories pick something like the beginning of the written record, or Mesopotamia. In any event, a date or event is picked before which there is taken to be no human history as we would define it. What we know about how our earlier ancestors lived is described as part of another discipline, perhaps anthropology or paleoarcheology. In On Deep History and the Brain, historian Daniel Lord Smail argues that the choice of a relatively recent date for the start of human history is more or less arbitrary and reflects the structure of an earlier conception of a “sacred history.” He proposes that the entire story of our species be integrated into the narrative of historians. He also offers some exciting suggestions for a possible approach to deep history centered around the human brain and nervous system.

The first two chapters are probably most meaningful to professional historians, but they’re accessible to any reasonably well-educated reader. Smail describes the way an earlier sacred narrative shaped our sense of history, and how vestiges of that narrative still shape our sense of when history began. Historians may reject the story of the garden of Eden, but history is still taken to begin at some base point in the human trajectory—perhaps the earliest farming communities, which contained the seeds of today’s world. Or maybe the fall of the Roman Empire takes the place of the expulsion from the garden, and we begin with the Middle Ages, relatively primitive compared to what came before or after. We still assume there is some starting point at which we open the book onto a human story, rather than recognizing the long gradual process by which we became what we are.

After outlining the history of our view of history, Smail considers and rejects a number of starting points that have been chosen for history. (Many of these arguments are no longer made by historians, but they still form a sort of ghost remnant of ideology that haunts our ideas of history.) He concludes that human societies don’t emerge into history when they start developing a written record, or when they demonstrate a consciousness of their own stories, or when they become politically organized, or when they cross some boundary line (e.g., 4000 B.C.) that separates human from animal societies.

But is there a dividing line inherent in the way humans are able to “transmit their experience to future generations [and] are in some sense the authors of the changes that happen to their societies”? Cultural evolution is Lamarckian, that is, acquired characteristics can be transmitted to others; this is in contrast to Darwinian biological evolution. Cultural evolution thus has an element of human control absent from human biological evolution. Could the advent of cultural evolution offer a justifiable breaking point after which we can legitimately consider human history to have started?

Smail examines this question in the third chapter of the book. He concludes that no, it does not. For one thing, we are not the only animals to have culture, and the cultures of other animals often lack a dimension of intentionality—as early human cultures quite likely did too. So on the far side of the divide, we have culture without much of a guiding hand. On the other side, more recent historical developments are not entirely intentional, but contain elements of chance and blind retention or transmission of changes (which are essential to Darwinian evolution).

He gives an example from his own research, an examination of how written descriptions of property, recorded in various transactions, changed over the later part of the Middle Ages. The parties to a transaction and the notary who recorded their verbal descriptions did not consciously plan to move toward any particular standard system for categorizing the properties, and yet the written descriptions did tend to eventually shift toward such a standard (which might vary from place to place). The shift was probably the result of slight unconscious preferences on the part of the notaries rather than any grand plan or design. In short, the division between Darwinian and Lamarckian factors is blurred rather than clear-cut.

I found the last two chapters to be the most interesting. Although there are many ways to approach a deep history of humankind, Smail proposes one centered around the capabilities and quirks of the human brain. The fourth chapter sketches out this “new neurohistory.”

An important part of this chapter is a critique of evolutionary psychology, which attempts to bring our preliterate past into the study of human societies today. Or rather, I should say it’s a critique of Evolutionary Psychology, although Smail doesn’t use the capitalization to distinguish between the application of evolutionary approaches to human behavior (lowercase evolutionary psychology) and the program laid out by Leda Cosmides, John Tooby, and others (Evolutionary Psychology, or EP). I’m very interested in the former but frequently skeptical of the latter.

When I read a news story about new EP research, I’m often baffled by the leap from the description of a newly identified behavioral trait to the story of why we behave that way. Surely, I think, I must be missing something. There must be something in the paper itself that explains the missing links between the observation of the behavior and the explanation of how it came about. Smail is a historian rather than a psychologist or anthropologist, but his understanding of the process of EP research parallels mine:

“Most work in evolutionary psychology is achieved through the process of reverse engineering—you look at the trait … and then try to imagine the evolutionary context in which it might have been adaptive. It is easy to make mistakes.”

At least I’m not the only observer who thinks imagination plays a key role in the explanatory process.

Smail describes several critiques of Evolutionary Psychology, in particular David Buller’s Adapting Minds: Evolutionary Psychology and the Persistent Quest for Human Nature. Buller makes three relevant arguments: First, natural selection does not homogenize human traits, but produces a diversity of psychological types (not along racial, ethnic, or gender lines, but within populations). I found this the most interesting of his arguments, because I’ve wondered for awhile about whether some personality traits are not adaptive or maladaptive in and of themselves, but might be necessary in balance with other traits within a population.

The second argument is that the human brain is not the product of a set of adaptations to a more or less fixed environment. The social intelligence hypothesis says basically that the development of human intelligence was driven by the need for understanding and relating to our conspecifics; if this is correct, then the shifting social environment gives rise to continuous adaptation of the human brain. The final argument is that the human brain could well have changed in the past 100,000 years rather than being frozen in its response to our ancestral environment.

The rest of the chapter deals with the necessity of taking biology, and in particular neurobiology, into account in history, for example:

“…moods, emotions, and predispositions inherited from the ancestral past, where they evolved at the intersection of human biology and human culture, form a structural backdrop for many things we do and have done. They are interesting for how they tease or suggest. They are also interesting for how they are violated, manipulated, or modulated. And this is precisely where it becomes so important to think with neurohistory. Although the fact is not widely known among historians and is generally overlooked by psychologists and biologists, cultural practices can have profound neurophysiological consequences. Key elements of human economic, political, and social activity … emerged precisely because humans possess relatively plastic or manipulable neural states and brain-body chemistries.”

There’s some shifting of focus here; neurohistory doesn’t necessarily have to deal with deep history (Smail includes examples of applications to more recent history), but taking neurobiology into account does set any historical study into the context of our story as a species. Although he explains in the preface his reasons for writing a book simply to propose this approach rather than trying to also sketch out what a deep history might look like, and his reasons are valid, I still wish the book had said a bit more about what might be covered in a new general history textbook that took the longer view he proposes. Maybe he’ll put that in another book. (And I do appreciate that this one was short enough to finish before I had to take it back to the library!)

A bit later in the neurohistory chapter, it says that the Neolithic revolution

“…created, in effect, a new neurophysiological ecosystem, a field of evolutionary adaptation in which the sorts of customs and habits that generate new neural configurations or alter brain-body states could evolve in unpredictable ways.”

Which is a good way of introducing the final chapter, which deals with a specific focus of neurohistory: psychotropy, or the ways humans manipulate the brain-body states of themselves and others.

Smail defines several types of psychotropy, although the definitions don’t seem to be mutually exclusive. First is teletropy, the influence of other’s moods and emotions through a variety of approaches that include things like religion or seduction. (I don’t remember that he specifically mentions art in this context, but it seems to me like another excellent example.) Teletropy can be symbiotic (both parties benefit) or exploitive, although it can be hard to draw the line, and it might be possible to describe the same behavior either way. (For example, is church-going a result of the joint interests of clergy and laity, or are the latter being exploited and duped into donating money to the former?)

In contrast to this is autotropy, the ways we have of adjusting our own mental and emotional state. These include recreational sex, reading, and gossip (taken to mean the discussion of other humans and their behavior). A subset of autotropic mechanisms that is also used sometimes in teletropy is the ingestion of substances that tweak our moods one way or another. The neurohistorical approach offers a new way to look at our relationship with these substances and practices over time, and this is the richest and juiciest part of the book, in my opinion. Toward the end of the chapter Smail suggests that:

“…it may be possible some day to argue that European societies, between the twelfth and the nineteenth centuries, witnessed a tectonic shift away from teletropic mechanisms manipulated by ruling elites toward a new order in which the teletropies of dominance were replaced by the growing range of autotropic mechanisms available on an increasingly unregulated market. (The rise of the fascist regimes of the twentieth century might well pose a challenge to the simple teleology of this model, reminding us that history is always complex and never linear.)”

I enjoy this kind of big-picture thinking, although obviously this is just the briefest of sketches to demonstrate the possible explanatory power of using a neurophysiological approach to human history. All in all, this book should provide plenty of fodder for thought and debate. Although it’s addressed to historians, I think there’s lots of material here to interest the more general reader, especially in the last two or three chapters.