Haim Ofek, Second Nature: Economic Origins of Human Evolution. Cambridge: Cambridge University Press, 2001. x + 254 pp. $27.95 (paperback), ISBN: 0-521-62534-3; $74.95 (hardback), ISBN: 0-521-62399-5.

Reviewed for EH.NET by João Ricardo Faria, School of Social Sciences, University of Texas at Dallas.

Remarkable books build their reputations by providing comprehensive and exhaustive answers to well established problems, or by setting a new agenda of research through the provision of new data and by looking at old problems with a new and fresh approach. This highly readable book of Haim Ofek falls into both categories. The book applies economic principles to understand many important issues in human evolution. However Ofek does not confine his analysis to economics. On the contrary, his assessment of the economic origins of human evolution relies heavily on literature, data and facts from anthropology, biology and other natural sciences.

In the introduction, Ofek exposes the issues and puzzles about human evolution that possess an important economic dimension -- such as the domestication of fire, the creation of stone tools, human migration from Asia to America in the midst of an ice age, the transition from the feed-as-you-go strategy through hunting-gathering and finally to agriculture, and the paradox of husbandry. The book addresses these issues in different ways: using available evidence, making logical inferences, and proposing new conjectures. Underlying the answers lies the main thesis of the book, that human propensity to exchange played a central role in human evolution.

The remainder of the book is divided in two parts: bioeconomics and paleoeconomics. Both parts are divided in six chapters. Chapter two deals with exchange in human and nonhuman societies. Ofek identifies two patterns of exchange, the nepotistic and the mercantile. Nepotistic exchange is regulated by evolutionary mechanisms such as kin selection and sexual selection, while mercantile exchange is purely human. Chapter three discusses the evolutionary origin of humans' predisposition to exchange. The key question is: Was exchange an agent of human evolution or merely a late by-product of human intelligence? The problem arises because the expansion of the human brain seems to be excessive relative to prehistoric needs for human survival. However, according to Darwin's principle of utility, natural selection cannot produce a structure that is harmful to an organism, nor a structure of greater perfection than necessary for an organism at a given stage in its evolutionary story. Alfred Russel Wallace (who shares with Darwin the creation of the concept of natural selection) concluded that forces other than natural selection were at action to explain the evolution of the human brain. For Ofek, exchange is the independent agent of brain evolution.

Chapter four considers the evolutionary implications of the division of labor to address the fundamental problem of human diversity in skills and talents. While the division of labor may happen in nonhuman societies, it never occurs in any significant way above the level of the organism or its immediate kinship group. Ofek attributes to mercantile exchange the capacity to enable the division of labor in human society to operate on a large scale within and across populations.

Chapter five makes an interesting link between the transitions from the feed-as-you-go model of subsistence to hunting-gathering to the peculiarities of human gut, which is markedly small relative to body size. In the feed-as-you-go strategy, food items are ingested on the spot and strictly in the order of acquisition. However, by following this strategy the feeder faces a trade-off between procurement and digestion. If it decides to minimize the energy cost in procurement, it will face the cost of digestion. On the other hand, if the feeder decides to minimize the costs of digestion, it runs the risk of starvation because of the costs of procurement. The hunting-gathering strategy solves this dilemma because it separates in space and in time the act of procurement from the act of ingestion and thereby, it minimizes both costs. As a consequence, the transition from a feed-as-you-go to a hunting-gathering strategy leads to a quantitative and qualitative improvement in the human diet, having an economizing effect on the digestive system. This transition is in line with the expensive-tissue hypothesis, which says that animals with cheap guts can afford expensive (i.e., large) brains.

The development of the argument in chapter six is less clear than in other chapters. The author attributes the origins of nepotistic exchange to the larger pool of primate inheritance. Ofek believes that humans are a more authentic representation of the common ancestral type than any other existing species among the hominoid species (e.g., gibbons, orangutans, gorillas and chimpanzees). The two major adaptive innovations of humans are the direct feeding investment in mates and offspring by the male and the loss of overt estrus and concealment of ovulation by the female. He also notes that another important difference lies in the reproductive behavior of humans, which display a diverse system of mating across cultures.

The natural history and social structures of the baboon are used in chapter seven to better understand some conceivable early indications for the existence of human exchange. The similarities between baboons and humans extend from diet to anti-predator behavior. However, baboons maintain a degree of genetic separation despite the absence of sharp geographical divides. Humans, on the other hand, lost this capacity for adaptive radiation and gained capabilities for adaptive specialization. Ofek argues that this was an inevitable outcome of the introduction of trade as a principle of organization in human affairs.

Paleoeconomics is the subject of part two of the book, which deals more explicitly with economic problems. Chapter eight explores the idea that trade was instrumental for the transition from the feed-as-you-go strategy to hunting-gathering. The main problem concerning the hunting-gathering strategy is food sharing or redistribution. Ofek claims that the only way to make economic sense of the food sharing for humans is to view it in the context of some form of market exchange. This is due to the fact that all organisms that rely on sexual reproduction have only two known options to redistribute the output of hunting-gathering activity: eusociality or market exchange. However, eusociality entails a lifestyle in which breeding is primarily limited to a single reproductive female, which is not the way humans evolved.

In chapter nine Ofek puts forward the exciting hypothesis that contrived commodities (characterized by exclusion and non-rivalry) provide an ideal starting point to construct a model of early exchange. The two entities most clearly identified as contrived commodities in prehistoric times are large game and fire, since any additional consumer willing to pay can be accommodated at no extra cost to the provider, and with no detraction in the consumption available to others. Incidentally, the domestication of fire is the subject of chapter ten. Ofek hypothesizes that fire by promoting trade was an agent of evolution, and civilization. He makes interesting conjectures concerning three important technical problems related to the domestication of fire: how to create, contain and keep it.

Chapter eleven considers the upper Paleolithic creative explosion. According to Ofek the refinement of upper Paleolithic tools suggests innovation in trade, increased division of labor and improvement in market structures. The most important and perhaps controversial conjecture of the whole book is that Ofek associates trade with human migration. Specifically, he conjectures that the incentives related to trade could be strong enough so as to justify migration and long-term occupation of harsh environment, such as the migration during the ice age from Asia to America.

The transition to agriculture is the object of chapter twelve. It is argued that a necessary condition for agriculture is climate stability, however this is not a sufficient condition. In chapter thirteen Ofek asserts that exchange is the facilitating factor for the transition to agriculture, since exchange reconciles the need for specialization in food production with the need for diversification in food consumption. Exchange also explains the paradox of husbandry (characterized by the fact that it takes more time and effort to raise and slaughter a domesticated animal than to hunt and kill its wild counterpart), as the meat obtainable from a domesticated stock is a highly durable commodity because it comes into human possession in a live animal.

As seen above, Ofek's book is in fact remarkable because it gives interesting, exhausting and insightful answers to old problems and, at the same time, it provides a new way to approach human evolution from the economic viewpoint. I hope it will stimulate the research on the economics of prehistory.

João Ricardo Faria is the co-editor with Amnon Levy of Economic Growth, Inequality and Migration, Edward Elgar, 2002, forthcoming. Among his recent articles are "What Happened to the Neanderthals? - The Survival Trap," Kyklos 53(2), 2000, pp. 161-172; "Habit Formation in a Monetary Growth Model," Economics Letters 73(1), 2001, 51-55; and "Testing the Balassa-Samuelson Effect: Implications for Growth and PPP," (with M. Leon-Ledesma), Journal of Macroeconomics, 2003, forthcoming.