Mystery of the rubber people

The Olmec are an oddity: they created a monumentally realistic art style in prehispanic Mexico but, after more than half a century of investigation, still lack cities, writing and most of the other traits associated with complex societies. Sometimes dubbed "America's first civilisation", their degree of social and political organisation is unknown, as are the most mundane details of their economy.

Even their ancient name is lost: "Olmec" means "the rubber people" and derives from the Olmeca-Xicalanca, who inhabited the gulf coast of Veracruz when Cortés arrived in 1519. The phrase was coined by Hermann Beyer in 19 when, reviewing Frans Blom and Oliver La Farge's Tribes and Temples , the pioneering monograph on this archaeologically unknown region, he linked a small greenstone figurine of distinctive style with the life-size squatting basalt statue on the mountaintop of San Martín Pajapan.

There had been earlier scattered reports: one of the Tres Zapotes colossal heads was found by José Melgar in 1862 and attributed to former occupation by a Negro race. Some things do not change: the notion that the Olmec heads depict Africans was still being used in the 1970s to support theories of transatlantic diffusion and their racist corollary that Native Americans were incapable of such artistic achievement. Olmec greenstone effigy axes bearing the faces of snarling supernaturals were noted in both the British Museum and the American Museum of Natural History before 1900, and the influential Mexican artist Miguel Covarrubias developed an enthusiasm for these and related jade carvings in the 1920s that did much to promote scholarly interest.

At the same time, Matthew Stirling of the Smithsonian Institution funded and did field research on the Olmec, for which he enlisted the aid of the National Geographic Society. The Olmec sites of San Lorenzo, La Venta and Tres Zapotes were exposed to a worldwide audience. At Tres Zapotes, Stela C's hieroglyphic text was deciphered by Marion Stirling as equivalent to 31 BC, the oldest written date in the New World. Ironically, the stela was (we now know) not Olmec at all, but the proposed reading aroused furious controversy, since it suggested that the Gulf coast cultures were older and more advanced than the Maya, the most famed of pre-Aztec civilisations.

The late Sir Eric Thompson argued with ferocious ingenuity that the Tres Zapotes date sprang from a different calendric base, and that the site's sculpture Ñ and, by extension, all known Olmec monuments - were of postclassic date, after the end of Maya civilisation c. AD 900.

The Stirlings disagreed, as did Covarrubias, and more importantly the great Mexican archaeologist Alfonso Caso, who in 1942 dubbed the Olmec the cultura madre , or mother culture, of Mesoamerican civilisation. The early date in the first millennium BC that they argued for was dramatically confirmed by radiocarbon dating later revealing that La Venta and San Lorenzo were among the oldest major sites in Mesoamerica.

Since 1960, an early date for Olmec society has not been in dispute, but just about everything else has: no urban sites are known (nor, for that matter, any villages), so the sobriquet of "civilisation", putting the Olmec on a par with early Sumer and late Predynastic Egypt, has appeared to some hyperbolic. The degree and intentional design of landscape remodelling at the largest site, San Lorenzo, and hence the level of labour and resource appropriation needed, has been doubted. Writing, and thus records of administration and government, are undiscovered, although symbols on a few monuments have been claimed as evidence of literacy. The massive stone sculptures remain the best evidence for Olmec social complexity, together with the numerous, although generally unprovenanced (and thus of uncertain date and genuineness) small carvings in hard stones, notably jade.

Some were displayed at the exhibition, Olmec Art from Ancient Mexico, at Washington's National Gallery of Art five years ago and discussed in its catalogue. John Clark and Mary Pye's book is the published record of a companion symposium (a rival show, The Olmec World: Ritual and Rulership, almost entirely of looted and otherwise unprovenanced pieces, was mounted in Princeton a few months previously). The sculptures are impressive: some of the dozen-and-a-half "colossal heads", known from San Lorenzo, La Venta and Tres Zapotes, are three metres high, and, like the massive oblong blocks known as "altars" or "thrones", weigh many tons. Their transport from the quarries in the Tuxtla mountains was a triumph of logistics, even if rafts were used to ferry the stones for much of the distance. Each of the heads is unique in its powerful facial features and headdress: that they are portraits is generally agreed, although whether those portrayed were living rulers or deified ancestors is not. Some heads were recarved from oblong thrones, suggesting arcane agendas. None has been found in its original context. Many of those at San Lorenzo were buried and the late second or early first millennium BC date ascribed to the San Lorenzo carvings on the basis of radiocarbon dates for domestic occupation several kilometres away was queried by the late George Kubler more than a quarter of a century ago.

There is a growing consensus that many of the carvings are centuries later: those from La Venta have long been proposed at 800-400 BC, and the highland site of Chalcatzingo has a floruit at 700-500 BC. The Olmec style, even in the Gulf coast region to which the term should properly be confined, looks awfully consistent to have persisted for eight centuries.

This proposed later dating has energised the debate about the role of the Olmec in the emergence of Mesoamerican civilisation, which burgeoned a decade or so ago in Regional Perspectives on the Olmec (R. J. Sharer and D. C. Grove, eds. 1989). Its contributors divided into two camps: those (mainly art historians, but with a few archaeologists) who believed the Olmec were the cultura madre , and those (mainly archaeologists, but with a few art historians) who saw them as a cultura hermana, a sibling society coeval with, linked to, but distinct from developments in other regions of Mesoamerica. Work in the central highlands of Mexico, the valley of Oaxaca and the Maya area has shown that each had, throughout the first millennium BC, its own autochthonous cultural tradition. Connections between these societies included not only trade in material goods such as obsidian, jade and other preciosities, but a shared set of ideas and images of the cosmos and the natural world. Whether there is a solely Olmec source for this ideological superstructure and the art in which it is manifested lies at the bottom of the argument: the autochthonist school sees the Olmec not as fons et origo , but only as primus (or even par ) inter pares .

Clark and Pye's book continues the debate less than providing new supporting material (although the confusion between radiocarbon and calendar dating is unhelpful): Richard Diehl summarises changes since Regional Perspectives while Barbara Stark sets the scene in terms of chronology and ecology; Stacey Symonds provides a broader hinterland for the crucial site of San Lorenzo; and Ponciano Ortiz and María del Carmen Rodríguez report further on the stunning wetland sites of El Manati and La Merced in its vicinity, with their offerings of effigy axes and wooden busts. Their radiocarbon chronology, apparently early but not without discrepancies, is vital for resolving the question of Olmec primacy in the emergence of the Mesoamerican belief system, especially given the contraindications that Richard Lesure reports from the Pacific coast of Mexico, the lack of early economic complexity in the Tuxtlas noted by Christopher Pool at Tres Zapotes and by Philip Arnold at La Joya, and the downplaying of Gulf coast links in central Mexico by Christine Niederberger.

Whether we should seek a single point of origin of any civilisation, be it Mesopotamian or Mesoamerican, is debatable: as we see with the first humans or the beginnings of agriculture, the vagaries of archaeological discovery keep shifting the focus. Over-emphasis on the Olmec has not allowed other peoples of early Mesoamerica their place in the cultural sun, but, as this book and its congeners show, they remain a topic of perennial fascination.

Norman Hammond is professor of archaeology, Boston University, Massachusetts, United States.