Tomlinson offers a new model for understanding this period in our emergence, one based on analysis of advancing human cultures in an evolution that was simultaneously cultural and biological—a biocultural evolution. He places front and center the emergence of culture and the human capacities to create it, in a fashion that expands the conceptual framework of recent evolutionary theory. His wide-ranging vision encompasses arguments on the development of music, modern technology, and metaphysics. At the heart of these developments, he shows, are transformations in our species’ particular knack for signmaking. With its innovative synthesis of humanistic and scientific ideas, this book will be an essential text.
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The last major transition
An important initiative in evolutionary theory crystallized in 1995, when John Maynard Smith and Eörs Szathmáry advanced the idea that the history of life on earth had passed through a small number of "major transitions." These were turning points at which decisive new kinds of organization appeared in living things and opened up new possibilities for subsequent evolution. Maynard Smith and Szathmáry saw the transitions not as deviations from the mechanisms of natural selection but as generated by them, enrichments and complications of Darwinian processes. By identifying jumps onto new levels of complexity and postulating the selective mechanisms driving them, "major-transition theory" formalized the idea shared by many scientists that the intricacies of natural selection could sometimes move in ways other than gradual, small-increment change. Another version of this idea in the years before 1995 had been Stephen Jay Gould's "punctuated equilibrium," long periods of stasis in the evolution of species interrupted by quick change and diversification. We can think of Maynard Smith and Szathmáry's transitions as very large, important punctuations.
The major transitions mark pivotal changes in the nature of life (Maynard Smith and Szathmáry 1995, 2000). They include the appearance of information-bearing RNA and DNA molecules, cells bounded within a membrane or wall, cells with nuclei and internal organelles, multicellular organisms, sexual reproduction, animal sociality, and, most recently, modern Homo sapiens. How pivotal this last transition was! After billions of years of evolution and many fundamental changes in the organization of life, something unprecedented occurred, a change that would, in a few dozen millennia, enable a single species to populate the whole globe, dominate all its ecosystems, genetically engineer plant species through thousands of years of cultivation, overwhelm or domesticate all other large vertebrate species, alter the planet's climate in fundamental ways, and finally set in motion a mass extinction. What made this last major transition so powerfully different from those that had preceded it, and how did it come about?
Two features reappear regularly in Maynard Smith and Szathmáry's transitions. First, they often involve a change in the target of selection, that is, a change in the entities on which natural selection operates. To exemplify this, we might think of the first development of multicellular organisms. In a world of single-celled life, about five-sixths of the history of earthly life, selective forces differentiated individual cells (or kinds of individual cells) from one another according to their fitness; this bacterial variety rather than that had greater fitness in a selective environment. Within an organism, however, selection and competition among individual cell types — our liver cells versus our skin cells, for example — would prove disastrous. Selective pressures on individual kinds of cells had to be somehow suppressed, operating instead to differentiate whole organisms. The target of selection had shifted from cells to organisms. The second feature that recurs across many of the major transitions is a shift in the nature of information transmission. The advent of sexual reproduction, for instance, involved processes of meiosis and fertilization that allowed for the shuffling, or "recombination," of genetic material, typically from two parent organisms, into a new amalgam. Compared with the various nonsexual reproductive modes of organisms, this represented a new organization in the passing on of genetic information from one generation to the next.
These two features were also important in the appearance of Homo sapiens, the most recent major transition; here too the transmission of information and targets of selection changed. In this case, however, they changed under the aegis of a new force that formed them in ways different from the other transitions. To this force we can assign a name: culture. And the kind of evolution in which culture played a role, marginally evidenced in some nonhuman life but hugely consequential in our lineage, is called biocultural evolution.
The book that follows is devoted to explaining the uniqueness of human biocultural evolution, and it might be regarded as a long footnote to Maynard Smith and Szathmáry's identification of our evolution as a major transition. Why is a book-length addendum necessary? The unvarnished answer is that scientists thinking about human evolution — or hominin evolution, to broaden the focus to include our closest extinct relatives — have not taken full account of the dynamics of culture. Putting culture in its proper place alters substantively our models of hominin evolution and so alters our picture of our evolutionary history, especially in its later stages, when culture loomed large.
I am not suggesting that scientists have not taken any account of culture in our evolution. It is no news among evolutionists that it is futile to try to separate off, in hominin evolution, our biological and cultural aspects, or that nature and nurture have developed in tandem with one another for millions of years in our lineage. (And also, arguably, in a number of other lineages of cultural mammals and birds, if with less dramatic results. Wondering why the runaway developments of the hominin lineage did not happen in these other lineages is a salutary exercise that points up the fact that there were selective paths other than snowballing cultural development along which these other species could achieve their own superb adaptive fitness.) But if evolutionists know that culture and biology cannot be separated, they have been slow to appreciate the full power of culture in the biocultural mix.
Human culture is something humanists and humanistic social scientists (for example, cultural anthropologists) are trained to interpret, discerning and differentiating its specific modes and, from these, arriving at its more general forms. But few scientists are so trained, and it should not surprise us that the premises about cultural dynamics they bring to the study of biocultural evolution are often less nuanced than they need to be. Add to this the proclivity of most scientists for quantitative-leaning explanations, so different from the humanistic, interpretive modes arguably essential for understanding culture and its patterns, and the case mounts that humanistic method needs to take its place at the heart of models of human evolution.
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Resolving the sapient paradox
This book does not take in all of hominin evolution but focuses on its latest stages, for it is here that the interplay of culture and biology grew especially intense in our phylogeny and, through this intensity (as I will argue), took on qualitatively new forms. I aim to explain how this burgeoning of human cultural capacities could occur over a span of time that is (evolutionarily speaking) very brief. The brevity is in truth dramatic: I am not alone in thinking that the most characteristic and complex features of human modernity were late attainments, not reaching back in their fully modern forms even as far as the advent of Homo sapiens. For example, there is much reason to think that the earliest sapient humans did not speak a fully modern language, even though their social communication was already more complex than that of any nonhuman species around us today. They did not create gods or spirits or form religious beliefs, they were not musical creatures in any modern sense, and in other basic aspects of their sociality they did not much resemble us. But then, in a blink of the earth's eye, they were transformed.
What kind of model will it take to represent this transformation? The model will need to offer a new resolution of a problem that has come to be known to paleoanthropologists as the "sapient paradox" (Renfrew 2008; Renfrew, Firth, and Malafouris 2008). The paradox lies in the similarity to us and difference from us of early sapiens. By about 200,000 years ago, after a long earlier development, they were physically so much like us, and so different from other early human groups such as Neandertals, that they are considered "anatomically modern humans"; yet they differed fundamentally from us in behavior and, it seems, in behavioral capacity. How could this be so? And how could all the ingredients of modern human behavior click into place without physical transformations noticeable in the fossil record? A satisfactory model must represent this change as quick and even abrupt but require no fundamental shifts in the biological nature of the creatures involved (if many smaller shifts) and no implausible, magic-bullet genes for language, music, religion, and so forth.
Foundations of hominin culture
Notwithstanding the countless evolved differences that entered into the hominin lineage across the last several million years, it is pretty clear that all hominin species have had several things in common, even if they have manifested them in very different form and measure. First of all, ancient hominins were all cultural animals, in a sense of that word that I can already begin to elaborate: they all witnessed behaviors in older individuals in their groups, repeated and learned these behaviors, and passed them on to younger individuals. This social transmission of learned behavior or knowledge across generations provides a straightforward baseline definition of culture, one that evolutionists such as Peter Richerson and Robert Boyd (2005) have used very productively.
This definition of culture is broader and also blunter than most of those advanced by anthropologists across the last century, but my project requires such breadth and bluntness. Working to define culture through induction from modern-day or recent historical cultures, as anthropologists have done, cannot help much to shed light on the earliest appearance of culture. The problem can be exemplified by citing almost any anthropological definition. Here is a famous one, offered in 1952 by Alfred Kroeber and Clyde Kluckhohn at the end of a book reviewing such definitions:
Culture consists of patterns, explicit and implicit, of and for behaviour acquired and transmitted by symbols, constituting the distinctive achievements of human groups, including their embodiment in artifacts; the essential core of culture consists of traditional (i.e. historically derived and selected) ideas and especially their attached values; culture systems may, on the one hand, be considered as products of action, on the other, as conditional elements of further action. (Kroeber and Kluckhohn 1952, 181)
And here is another, simpler but equally famous, offered twenty years later by Clifford Geertz, perhaps the most influential anthropologist of the second half of the century:
the culture concept ... denotes an historically transmitted pattern of meanings embodied in symbols, a system of inherited conceptions expressed in symbolic forms by means of which men communicate, perpetuate, and develop their knowledge about and attitudes toward life. (Geertz 1973, 89)
As sophisticated as they are, these definitions presume what any deep-historical account of the emergence of human culture must instead set out to understand. They can gain no purchase on hominin cultures before there were symbols or symbolic cognition — cultures that did not frame "attitudes" toward life or mark distinctions of one social group from another, cultures made by animals without language. I will engage with such anthropological definitions of culture (and also of another important anthropological concept, ritual) only in chapters 6 and 7, where I offer an account of human behavior taking on its modern form. These definitions cannot serve as my starting point, however, for that would be to take the explanandum as explained. We must begin with more foundational stipulations.
Richerson and Boyd's definition of culture suggests two of these — additional shared features of hominins that reach far back in their phylogeny. In order for the transmission of learned behavior to happen, they all must have been animals capable of looking to their species-mates — their conspecifics, as ethologists call them — and imitating them, thereby adopting the behaviors of those others and in general learning from their social surroundings. In an important book of 1991, evolutionary psychologist Merlin Donald took this imitation, which he termed mimesis, as the fundamental trait of a long period of hominin evolution, a period of "mimetic culture" extending from almost two million years ago down to the advent of Homo sapiens. Donald's mimesis required special capacities on the part of the animals that performed it: capacities to shape voluntarily mental "representations" of perceived actions, capacities novel in the hominin line that differentiated hominin mimesis from the less voluntary and less self-conscious mimicry of other animals. These voluntary action plans made possible cultural transmission and the imitative pedagogy of cultural behaviors long before language existed.
Such mimesis was founded on another general capacity: the ability to understand in some fashion the intent behind a conspecific's actions. This ability could lead to imitation through a projection of one's own intent onto another individual: "I want to crack a nut; she wanted to crack a nut; I should take a stone and do it that way." This kind of mechanism seems close to Donald's voluntary formation of mental representations. It involves, it is clear, an impressive cognitive feat, one that is not widespread in the animal world today: the sensing of a mind similar to one's own at work in another individual. This capability is known by various terms among scientists today, but most commonly it is called theory of mind. Theory of mind comes in several degrees of complexity, and it is probably found among some mammals and birds today in something like the degree to which it was manifest at some very early stage of hominin evolution. In the hominin lineage, however, it eventually outstripped the forms it took in any other. This development was of fundamental importance for what followed in the course of human evolution, and I will have something more to say about it at the end of chapter 4.
For the most part, however, I will not linger at this early stage of hominin evolution. Instead, I focus particularly on the final emergence of our modernity — roughly, across the last 250,000 years — and I aim to illuminate the special dynamics that entered into these final stages. There are two general reasons for this focus, which derive from the successes as well as inadequacies of the earlier literature. On the one hand, the models developed elsewhere for the growth of early hominin capacities — especially theory of mind, mimetic capacities, and social learning, the basic precursors of cultural elaboration — are compelling, and I accept and exploit them. On the other hand, the models do not satisfactorily explain the recent, explosive emergence of cultural modernity among one or a few species of hominins. This explosion marks a final, dramatic divergence of hominin evolution from the evolution of all other lineages, even other lineages of animals that can be thought to have cultures. And this is the heart of the problem of our emergence, the essence of the sapient paradox, and the feature that makes late hominin evolution fatefully and fundamentally different.
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Coevolution and niche construction
Understanding the burgeoning of our modernity requires revising and enriching the available models of the place of culture in our evolution. In doing this I will not depart, any more than May-nard Smith and Szathmáry did, from the basic mechanisms of the evolution of life: inheritance of traits, variation in them, and selection among the variants. Instead, I attempt to understand new dynamics that emerged from the fundamental Darwinian mechanism of inheritance-variation-selection under the special conditions of late hominin cultural development. In this too my account is related to major-transition theory, though it discerns, in this last transition, cultural forces at work that differ from those described by earlier theorists.
To construct my model of hominin evolution I will move along two paths. The first, pursued in chapters 2 and 3, describes and elaborates a dynamic of biocultural evolution that biologists have explored over the last forty years or so. Though much of the material in these chapters will be familiar to evolutionary scientists, I introduce into it a new mechanism and new emphases that point toward the cultural model described in subsequent chapters. The key concepts here are coevolution and niche construction, terms that are associated today with novel extensions of Darwinian natural selection theory — the so-called "extended evolutionary synthesis" (Laland et al. 2015; Pigliucci and Müller 2010).(Continues…)
Excerpted from "Culture and the Course of Human Evolution"
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Table of ContentsPreface Chapter 1 Introduction
Chapter 2 The Consequence of Feedback I: Coevolution
Chapter 3 The Consequence of Feedback II: Niche Construction and Culture
Chapter 4 Hominin Culture from the Bottom Up
Chapter 5 Systematic and Emergent Culture
Chapter 6 The First 150,000 Years of Homo sapiens
Chapter 7 The Gathering of Modernity Acknowledgments