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The Incredible Human Journey: The Story Of How We Colonised The Planet (Book Review)

Alice Roberts
Bloomsbury 2009
(pp 376)

(October 2009) (Forthcoming) First appearance of this review article to be in: Skeptical Adversaria (2009) or Skeptical Intelligencer (2009)

Reproduced with permission

This book, linked with a recent BBC TV series, is an exciting travelogue-cum-intellectual detective story in which Alice Roberts very ably discusses the matter set forth in her title. Some of the major associated issues now appear to be nearing resolution, notably the question of whether homo sapiens (‘we’) evolved from our immediate forebears once only (‘Out of Africa’) or several times and in different locations (‘multi-regionalism’) – although well-informed dissenters remain (see below). And, while some other points of contention are still very much ‘up in the air’, the time for such a book, scholarly but accessible to non-experts, has arguably arrived. Roberts herself is an evolutionary anatomist with a PhD in palaeo-pathology, and this aspect of her work is naturally especially strong; but she has informed herself well on other relevant subjects and has used her academic contacts most effectively in drawing off expertise across this entire multi-disciplinary field of enquiry.

In the wake of the earlier expansion of homo erectus (in East Asia by 1,000,000 BP), homo sapiens was established throughout the entire habitable world by 1000 CE (New Zealand was the last sizeable land-mass to be reached); indeed, in many areas remote from our African cradle (including Australia; now also the Americas, e.g. at Monte Verde in Chile) the archaeological/palaeo-anthropological record displays a much longer settlement history (20,000-60,000 years). During this process, other hominin species (including erectus and the Neanderthals) were, it appears, completely replaced (though see below).

Genetically and physiologically, sapiens displays little diversity; all ‘interracial’ physical differences are superficial. On the other hand, the unprecedented ability of sapiens to learn, reason and speculate during its lifetime, and to transmit this acquired information to its offspring, has led to the enormous cultural diversity which distinguishes human communities – including the existence of many divergent religions and world-views, many forms of art and symbolism, and thousands of mutually unintelligible languages. Other species can of course communicate, but none – even our closest primate relatives – are known to have art, religion or language as such. The origins of religion and language remain obscure, because of the ephemeral nature of most of the empirical evidence in these domains before the recent invention of writing; but with increasing sophistication in the relevant disciplines – now including genetics, especially work on mitochondrial DNA, and various new (and in some cases still controversial) methods of dating – much can now be learned about the prehistoric stages of these characteristically human behaviour patterns and their subsequent early differentiation. All human groups also share crucial tool-making abilities not found in other species; and tools (and other artefacts) have themselves diversified very considerably, as the archaeological record shows. And all of this varied information is grist to Roberts’ mill.

Roberts traces the origins and history of sapiens as revealed by the ever-growing tradition of scholarly work, and also the history of that tradition (‘lumpers’ vs ‘splitters’, etc). She recounts meetings with advocates of all the relevant mainstream standpoints, including for instance her adventures with Robert Bednarik – one of the few remaining advocates of multi-regionalism – and with Chinese scholars, some of whom have posited a startlingly strong version of multi-regionalism in the context of the origin of their own population. And she includes a fascinating excursus on the newly-discovered ‘hobbits’ of Flores, which some scholars regard as a non  sapiens population which became extinct only a few thousand years ago. (See now Kenneth Krause’s article in Skeptical Inquirer 33:4 for an update on this debate.)

Roberts is not afraid of addressing politically sensitive topics, such as the issue of the role of sapiens in the extermination of the Pleistocene megafauna in Australia (also relevant in the Americas). And, while she does not tangle with the fringe proper, she cheerfully deals with the better-informed minority theories involving surprisingly early transoceanic links between the Americas (generally thought to have been settled mainly via Beringia) and remote areas (Africa, Australia and the European sites of the ‘Solutrean’ culture).

As a historical linguist, I might have liked to find in this book a somewhat greater focus on linguistic matters. The highly specific and vastly complex details of language data often furnish key evidence in the assessment of historical and archaeological theories; and, although much of the period surveyed by Roberts is pre-literate, such comparative evidence as may be gleaned from known (or reconstructed) languages, spoken or written, is still important. Roberts does include an interesting (though, it must be said, somewhat naively-expressed) discussion of ‘click’ consonants (technically, velaric ingressives) in a range of African languages, comparing their distribution with genetic data and suggesting (with others, and not unpersuasively) that the development of these phones may well have pre-dated sapiens expansion from Africa. She also rehearses the diffusionist geneticist Stephen Oppenheimer’s ideas about links between the distribution of alpha-thalassaemia and early language community boundaries in South-East Asia; these, again, carry a degree of conviction, though Oppenheimer’s linguistics itself leaves something to be desired. But more along these lines, and more palaeo-linguistics generally, would perhaps have been welcome.

Roberts writes well and clearly, and obviously with passion as well as scholarship. Overall, the work cannot be recommended too highly to all with an interest in these matters.