The Incredible Human Journey

The Incredible Human Journey (2009) is one of the most exciting and also one of the most comprehensive documentaries on prehistoric human migration out of Africa. In her quest to trace the human journey, anthropologist Alice Roberts travels around the world, visiting the most scenic environments across the five continents, meeting with rare tribes living traditional lifestyles, discussing important archaeological sites and talking to various specialists. No expenses are spared and the result is over four hours worth of great footage that will speak to anyone, regardless of their prior knowledge or even interest in this topic. Throughout the documentary, several mainstream theories on early human migration are discussed in an accessible way. Most of the information is accurate and up-to-date, although I do have some minor comments. In order to give you an idea of the contents of the documentary, I will discuss all five episodes below.The_Incredible_Human_Journey
Out of Africa
The first episode focuses on Africa, the continent where it all started. Most of the episode is dedicated to explaining in depth how all humans alive today share a common ancestor from Africa, which has been the mainstream theory for the last fifty years and has pretty much been proven since the development of modern genetic genealogy during the 1980s. As such, this episode does not contain much new information for those who already have a basic understanding of human evolution. Personally, I think they could have spent more time on discussing the more controversial points. Nevertheless, Alice Robert’s visit to the Great Rift Valley, where the earliest identified remains of homo sapiens sapiens have been found, and her meeting with the Khoisan hunter-gatherers, who still live in much the same way as our earliest common ancestors, were great ways to fuel the imagination. Moreover, the visit to Pinnacle Point, at the southermost tip of Africa, where very early human remains have been found, shed some light on early human migration within Africa itself; something that is often overlooked in favor of discussing human migration out of Africa and beyond. Furthermore, the discussion on the most likely route that the earliest modern humans who left Africa took was an interesting addition, since there is still some controversy on this. Nevertheless, the migration out of Africa via Yemen, as proposed by Roberts, seems to be the dominant one as of now.

Asia
In the second episode of The Incredible Human Journey we find that Alice Roberts has traded the hot savannah of Africa for the frozen tundra’s of Siberia, where she meets an entirely different tribe of hunter-gatherers: one of reindeer hunters. After posing the question how people from Africa could have adapted to such a cold environment and changed their appearance so much along the way, Robert’s suddenly introduces a strange, outdated theory: the multiregional hypothesis. This hypothesis proposes that different ‘races’ of homo sapiens sapiens evolved independently from each other from different groups of homo erectus. This hypothesis has been abandoned for over fifty years and even before that date it was mostly defended by racists. Apparently, however, many Chinese anthropologists still defend this view, claiming that the ‘Mongoloid race’ is descended from a branch of homo erectus known as Peking man. At first Roberts presents the arguments in favor of this hypothesis in a serious way, almost making you believe that she herself believes it. The arguments are mainly based on old-fashioned arguments like a comparison of skull shapes and facial features. Then, however, Roberts and ‘believer-turned-skeptic’ Jin Li come along with the fancy new invention of genetic genealogy, which proves beyond a doubt that the Chinese people, like everyone else, are descended from people who migrated out of Africa.

Chris Stringer's hypothesis of the family tree of genus Homo, published 2012 in Nature: Homo floresiensis originated in an unknown location from unknown ancestors and reached remote parts of Indonesia. Homo erectus spread from Africa to western Asia, then east Asia and Indonesia; its presence in Europe is uncertain, but it gave rise to Homo antecessor, found in Spain. Homo heidelbergensis originated from Homo erectus in an unknown location and dispersed across Africa, southern Asia and southern Europe (other scientists interpret fossils, here named heidelbergensis, as late erectus). Homo sapiens spread from Africa to western Asia and then to Europe and southern Asia, eventually reaching Australia and the Americas. In addition to Neanderthals and Denisovans, a third gene flow of archaic Africa origin is indicated at the right.
Chris Stringer’s hypothesis of the family tree of genus Homo, published 2012 in Nature: Homo floresiensis originated in an unknown location from unknown ancestors and reached remote parts of Indonesia. Homo erectus spread from Africa to western Asia, then east Asia and Indonesia; its presence in Europe is uncertain, but it gave rise to Homo antecessor, found in Spain. Homo heidelbergensis originated from Homo erectus in an unknown location and dispersed across Africa, southern Asia and southern Europe (other scientists interpret fossils, here named heidelbergensis, as late erectus). Homo sapiens spread from Africa to western Asia and then to Europe and southern Asia, eventually reaching Australia and the Americas. In addition to Neanderthals and Denisovans, a third gene flow of archaic Africa origin is indicated at the right.

Europe
The episode about Europe focuses mostly on the first migration wave, that came from the Middle East around 40.000 BP and brought with it Cro Magnon man. A later wave came from the Eurasian steppes. One of the most enlightening parts of this episode was the reconstruction of the facial features of one of the earliest Europeans, based on its skull. The facial features of the skull resemble neither modern sub-Saharan Africans nor modern Europeans. This indicates how easily physical characteristics can morph over the generations. The distinct looking groups that some call races are simply snapshots of human evolution. These ‘races’ are no more than macrofamilies that became succesful at multiplying following the agricultural revolution. Moreover, because these groups interbred from an early date onward, the boundaries between these families are nearly impossible to draw. The episodes also discusses the Neanderthals and emphasizes that they were nearly as intelligent as modern man. Roberts also goes out of her way to state that Neanderthal and Cro Magnon man did not interbreed, even though it has recently been proven that they did. In fact, all non-African populations have about 2% of genetic Neanderthal admixture. This is not the same as the multiregional hypothesis, however, as the vast majority of Europeans are still descended from Africans. They have only absorbed some Neanderthal elements.

Australia
The episode on Australia is one of the most interesting, since it actually traces one of the most important migration routes of early man: the Coastal Migration Route. The earliest humans to have left Africa, over 70.000 years ago, followed the route along the coasts of the Indian Ocean until they reached Australia and, after travelling further along the Pacific Coast, also the Americas. Alice Roberts takes the viewer by the hand in this journey of discovery, starting with the fact that the earliest human remains in Australia, at Lake Mungo, date back to 40.000 years BP and probably even predate the earliest modern humans in Europe. Roberts then explores a few improbable explanations for how early humans reached Australia from Africa, before putting forward the arguments for the Coastal Migration hypothesis. Up until recently, evidence of early humans along the coast of the Indian Ocean predating the Lake Mungo finds was rare, but a site in India has now revealed that modern humans had lived in the region before the eruption of the Toba supervolcano around 70.000 BP, as these remains were found beneath its ash layer. Furthermore, although this is not mentioned in the documentary, Y-DNA haplogroups C and D, that are also present in Oceania, are found all along this coastal route. These early migrants out of Africa were probably pretty dark skinned, like the Australian aboriginals and the Negrito populations living on small islands just off the coast of Indian Ocean. Roberts also discusses the remarkable choice by these early migrants to cross the Torres Strait from Indonesia to Australia and conducts an experiment with a simple raft to demonstrate how people could have crossed the sea.Spreading_homo_sapiens_la

The Americas
The final episode deals with the arrival of modern humans in the Americas. One thing I like about this episode is that it juxtaposes a traditional theory to a fairly new one. The traditional belief was that the first modern humans reached the Americas via a land bridge across what is now the Bering Strait around 13.000 years ago, giving rise to the Clovis culture. However, human remains predating this migration have now been found across the Americas; from California to Texas and from Chile to Brazil, but mostly situated along the Pacific coast. These people couldn’t have arrived via the land bridge, however, since it was only ice free for a relatively short time. The new and already largely accepted theory is that of the coastal migration, which basically extends the coastal migration along the Indian Ocean to the Pacific Ocean. These coastal migrants, again carrying mostly haplogroup C, traveled along the coastal islands of the northern Pacific in small boats. The later migrants over the Bering land bridge, who carried haplogroup Q, eventually became the dominant group in the Americas. This episode was probably the best and it even presented some information that was new to me.

Conclusion
All in all I highly recommend this documentary, especially if you have little prior knowledge about this subject. The footage is beautiful and I have always had a weak point for experimental archaeology. The narrator does a good job at explaining the methods by which scientists arrive at their conclusions. She usually starts off by asking a question and pretending not to know the answer, she then proposes some non-mainstream theories and explains why they are most likely wrong, and finally she presents the evidence in favor of the mainstream theory. My greatest criticism is that this documentary spends too much time trying to ‘debunk’ the multiregional origin hypothesis, a theory that has long been abandoned and, as far as I know, isn’t a widely held belief among laypeople. I suspect that this is mostly due to the fact that physical anthropology and genetics have a somewhat controversial air around them, since both disciplines have been used in the past to justify racism. In order to discuss genetic and phenotypical diversity without appearing racist, the makers of this documentary have (in my opinion) been a little too concerned with explaining how ‘we are all family’ and how everyone who states otherwise is wrong. This is admirable, but also a little patronizing towards the intelligent viewer. Besides, Alice Roberts even goes as far as stating that there was no interbreeding between Neanderthal and Cro Magnon man, while this fact was proven soon after the release of this documentary. In my opinion, they could have used the time spent on debunking the multiregional hypothesis to address controversies between several current mainstream theories and leave it up to the viewer which conclusions to draw.

Watch or read
Here are the links to the five episodes:

Out of Africa (1/5)
Asia (2/5)
Europe (3/5)
Australia (4/5)
The Americas (5/5)

There is also a book based on this documentary. You can find it here.