A Troublesome Inheritance: Genes, Race, and Human History. By NICHOLAS WADE. Penguin Press, 2014, 288 pp. $27.95.

It is hard to disagree with the journalist Nicholas Wade when he writes in his new book, A Troublesome Inheritance, that “human evolution has been recent, copious, and regional.” Modern humans first began dispersing around the world about 50,000 years ago, as small bands of around 150 individuals departed their ancestral homeland in Africa to form new colonies elsewhere. And those settlements eventually sent out pioneers of their own, and so on, for tens of thousands of years. Over time, humans were exposed to intense evolutionary pressures that varied according to each population’s local climate, geography, fauna, and flora.

For example, the ancestors of contemporary East Asians and Caucasians, forced to cope with the long dark winters of the north, evolved pale skin, most likely because this trait enabled the individuals who possessed it to absorb more light and synthesize vitamin D, and thus to survive and reproduce more successfully in dark areas. Other genes found to be modified by natural selection are linked to diet, skeletal and hair structure, fertility, resistance to disease, violent aggression, and general brain function. Many of these variations have evolved within the last 15,000 years and affect specific populations: Tibetans, for instance, are thought to have developed the necessary changes in blood cell regulation required to thrive at high altitudes a mere 3,000 years ago.

The basic biological facts of human evolution are indisputable, and A Troublesome Inheritance is correct to point them out. Wade, however, is interested in more than biology: he is also interested in how biological differences among populations have led to social and political differences across societies and vice versa. Wade argues that it's possible to trace how genetic evolution produced behavioral capacities -- and, by extension, social institutions -- that differ among populations. “The genes of the nervous system,” he writes, “have been under selection for the same reason as the other genes -- to help people adapt to local circumstances. Changes in social behavior may well have been foremost, given that it is largely through their society that people interact with their environment.”

Wade is not the first writer to pursue the idea that genetic differences can explain differences in behavior across societies. And he adheres to a particularly sophisticated form of this line of thinking: he has developed an intriguing theory to explain how biological evolution and social evolution might be interlinked. But ultimately, Wade's theory has far less explanatory power than he seems to believe. At crucial points in his book, he draws conclusions far in excess of what a reasonable reading of the biological evidence would allow. At these moments, A Troublesome Inheritance ceases to be a scientific inquiry into race and becomes something rather more troubling.

CULTURAL EVOLUTION

Wade’s theory begins with the transition from hunter-gatherer society to settled society, which brought with it new evolutionary pressures. As people took to agriculture and animal husbandry, human populations expanded and the specialization of labor became a necessity. Along with specialization came hierarchy, since those individuals with, say, social skills, self-discipline, and cognitive ability now stood a reasonable chance of becoming wealthier than their less gifted neighbors. The benefits of such behavioral qualities began to accrue to individuals and their descendants rather than to the tribe as a whole, as had previously been the case; private wealth allowed for the support of more children, and these many children could, when there was no available mate of similar status, select marriage partners from the most successful families of lower social rank. The genes of society’s most successful individuals would thus, over many generations, increase in frequency among the general population.

Evolution, Wade points out, never stops, and thus as tribes developed into chiefdoms, chiefdoms into states, states into empires, and empires into civilizations, new social environments selected for new behavioral traits. This process gently molded the genetic makeup of the average human being within different populations, with significant cultural consequences.

This is an entirely plausible thesis. Culture both shapes and is shaped by human behavior, and there is very good reason to believe that behavioral inclinations can be hereditary. For example, the Russian geneticist Dmitri Belyaev demonstrated that wild foxes can quickly be bred to become domesticated animals. Over a period of 50 years, Belyaev managed to create a breed of fox that, like many dogs, possessed floppy ears and piebald coats and displayed an active desire for human company, whining for the researchers’ attention and wagging their tails when humans would walk by or pet them. It is sometimes easy to forget the fact that, genetically speaking, humans are not so different from Belyaev's foxes, insofar as Homo sapiens is an animal whose genome, which includes every gene relating to cognition and behavior, is subject to evolutionary pressures.

SOCIOLOGY VS. BIOLOGY

But Wade’s purpose is as much sociological as biological. An initial indication of this is given by his classificatory terminology. Instead of using the neutral biological term “population” to describe variants in the human population, Wade uses the contested sociological terms “ethnicity” and, more often, “race” (of which he claims there are at least three nondiscrete types: African, East Asian, and Caucasian). This word choice buttresses Wade’s claim that biological race has become a taboo subject, a fact he takes issue with on the grounds that the “analysis of genomes from around the world establishes that there is indeed a biological reality to race.” Geneticists, however, disagree about whether or not race is a useful and coherent biological concept. In fact, Wade himself admits that genetic variation is what biologists call “clinal” -- that is, it is mostly gradual and exists on a geographic continuum -- and, as such, defining race is to some extent a discretionary exercise. As is the case in many scientific fields of study, exactly where one chooses to draw conceptual boundaries inevitably reflects one’s own scientific goals.

For his part, Wade seeks to explain why many African nations are destitute and racked by internal conflict, why East Asian societies are becoming richer but remain stubbornly conformist, and why Caucasians (excepting non-Jewish Middle Easterners) have come to possess open societies and disproportionate influence in global politics. He suggests that because of the wide variation in social and natural environments that different races and ethnicities have historically experienced, there are some biological reasons, rooted in the genetics of race, for why the world's present social and political arrangements look the way they do.

But Wade’s arguments in support of this hypothesis are deeply problematic. His evidence is sparse and usually contested, his concepts are often flimsy, and he repeatedly makes logical leaps powered only by assumptions and speculation. In the scientific community, there is widespread skepticism that it is possible to know the specific effects that genes have on social behavior. Wade doesn't refute this skepticism so much as he simply ignores it.

This raises the question of why Wade, in considering the origins of disorder and poverty in the developing world, is so eager to reach for biological explanations, rather than the vast stores of historical and political knowledge that are available. Wade rarely considers the effects of outside political interference in the developing world, including colonialism, incessant superpower interference during the Cold War, and more recent military interventions in Iraq and Libya; the numerous tariffs and other barriers to trade that some wealthy countries use to undercut agricultural imports from poorer ones; the destabilizing and sometimes predatory lending practices of multinational banks, the International Monetary Fund, and other creditors; and public health crises such as malaria and HIV/AIDS.

Wade prefers to focus instead on indigenous obstacles to development, such as nepotism, corruption, and endemic violence. It's possible that some of these obstacles may be affected by behavioral tendencies that vary regionally as a result of local evolutionary pressures, but Wade’s concept of race is too broad and too brittle to have explanatory power in this regard. Wade fails to recognize that a biological concept cannot explain a phenomenon as complex as modern world history.

At certain points of the book, he unwittingly reveals the weaknesses of his argument. Consider, for example, his declaration that “the rise of the West was not some cultural accident” but rather “the direct result of the evolution of European populations as they adapted to the geographic and military conditions of their particular ecological habitat.” But by Wade's own classification scheme, western Europeans are not at all coterminous with the Caucasian race -- a classification that, he says, encompasses peoples living in countries as different as Iceland, Iran, and Israel. This implies that the genetic differences captured by Wade's race concept are not determinative of a group's specific social and political adaptations. But Wade refuses to draw that conclusion.

Nor does he mention some of the more unflattering implications of his thesis for contemporary Westerners. Wade notes that “a distinctive feature of genetically shaped behaviors is that they persist unchanged over many generations.” But Wade never considers the ample historical evidence that the most ostensibly successful Western social adaptations are linked to destructive social tendencies.

For example, if we follow Wade’s logic, it stands to reason that nature may have selected for traits other than intelligence and self-discipline -- manipulation and predation, for example, or hardheartedness, greed, and moral self-deception. In fact, the wealthiest Americans give, as a percentage of their incomes, only about half as much to charity as do the poorest. This might also explain why sociopathic tendencies -- which are thought to be partially hereditable -- have been found in some four percent of CEOs compared with around one percent of the general population. Meanwhile, bright and disciplined elites who are particularly compassionate have always been in danger of quickly losing their wealth and status.

A NEW AGENDA

In spite of A Troublesome Inheritance’s shortcomings, Wade is right to encourage debate on an important set of issues that too often gathers dust for fear of causing some unspecified offense or discomfort. That people worry about the scientific exploration of group differences is of course understandable: biological rationales have been used to justify the oppression, enslavement, and murder of so-called lesser races. By the same token, however, the Soviet dictator Joseph Stalin outlawed research in classical genetics on the grounds that it conflicted with the egalitarian foundations of Marxist ideology and sent many of the scientists who dared explore the field to their deaths in Siberian labor camps. As Wade is at pains to point out, it is therefore not so much scientific research and its discussion that pose dangers to society, but rather the ideology of the establishment within which this debate is conducted. It hardly needs mentioning that today’s intellectual and political establishments are very different from those of the 1930s. Although caution is prudent and necessary, we ought not to jump at every shadow when talking about human differences.

A Troublesome Inheritance should stimulate reflection among those who, mistakenly, continue to believe that the environment alone can adequately account for all variation in human behavior and, subsequently, in life outcomes. We know that substantial genetic variation occurs within the human species. We know that some of this variation exhibits regional patterns, that some of it affects cognition and behavior, and that much of it has evolved very recently. These are demonstrated facts, and their discovery is important; any further research they inspire will have significant consequences for many fields of study. It will also have implications for public policy. Genetically targeted health care stands out in this regard, but crime prevention programs, education, and the provision of social services may also be affected.

Nevertheless, Wade does not adequately acknowledge the many deficits of knowledge in the field of human genetics. The reality is that we are not yet able to determine the exact role of genes in determining life outcomes. As a result, any attempts to interpret genetic variation within our species, classify its distribution, and formulate any theory or policy on its basis should do so with conceptual circumspection and sensitivity. To insist on this is not to kowtow to political correctness, but simply to appeal for good social science, good sense, and good manners. In these respects, Wade’s book is wanting. One can only hope that his next attempt to tackle the many pertinent and pressing questions surrounding the nexus of genes, behavior, and society will correct these failings and will be better matched to the present state of genetic research.