The British archeologist Timothy Taylor argues that technology is the solution to this apparent contradiction. Evolution is not only biological. The cultural-technological component is equally important, and it vastly favored humans over any other species. Technology is very much part of what we mean by "being human". Darwin's theory of evolution needs to be complemented with a story of how technology allowed humans to violate the very rules that Darwin found embedded in all other species. According to Darwin's blind algorithm of natural selection, humans should have gone extinct very quickly. Biological evolution (or, better, biological accident) accounts for humans developing the upright posture. That posture freed the hands, and allowed humans to make tools. That situation completely altered the normal course of biological evolution because, from that point on, technology introduced a parallel (non blind at all) algorithm. Humans started evolving not based on biological laws of evolution but based on technological factors. Taylor claims that "technology evolved us".

This, however, leads to a vicious loop. Technology requires a smart brain to design it and build it; but a smart brain requires a lot of proteins which come from hunting, fire and cooking, which are made possible by technology. Therefore technology requires a brain that is made possible by technology. It is a "chicken and egg" kind of problem: one cannot exist without the other, but one must have come first.

Taylor points out that humans seem to go against evolution: we are "biologically reduced". Our bodies have weakened since the Stone Age and keep weakening. We are less strong, less agile, less fast, etc than our prehistoric ancestors were. Something similar happens to wild animals when they get domesticated. By analogy, Taylor calls "self-domestication" the process by which humans got weaker while becoming more dependent on technology, i.e. while developing a smarter brain. This is another strange loop: it could be that brains got smarter as bodies got weaker, or it could be that bodies got weaker as brains got smarter. In fact, it is not even true that human brains got larger since prehistory: the human brain has shrunk about 10% over the last 10 thousand years. The Neanderthal man was not only stronger than Homo Sapiens: it also had a bigger brain and perhaps was in many ways smarter. But it was Homo Sapiens that survived, and went on to rule the planet. Taylor calls it "survival of the weakest". Taylor is convinced that tools, the great invention of Homo Sapiens, dramatically altered the terms of evolution.

The first chapter lays out the general idea. The other chapters are meant to provide the evidence. The evidence is not terribly convincing. The chapter on the Tasmanians, people who puzzled archeologists because they remained so primitive (running naked in a cold climate and never learning how to fish in an island surrounded by millions of fish), is particularly unconvincing: Taylor argues the Tasmanians never "wanted" to wear clothes nor to fish nor to make tools (they only had about 20). He argues that from the point of view of a Tasmanian wearing clothes may have looked like a trait of savagery, not of civilization: you can't live without clothes, you poor savage? Interesting theory, but far-fetched.

Another interesting theory (and this one much more rational) is that humans did not evolve the ability to make tools (which requires big brains which require tools) but tools caused humans to evolve that way. Chimps don't have big brains because they need the skull configured in such a way to allow for their powerful jaws. Having fire and tools, humans did not need those powerful features of the head and therefore lost them and therefore space was left over for a big brain to grow. He points out (page 82) that there is a gap beween the date of the oldest chipped stone tool (2.5 million years ago) and the first hominids (2.3 million): 200 thousand years, a very long period of time.

The chapter on cooking is particularly interesting because it is not so much about the importance of fire and cooking meat (that many books have analyzed extensively) but about cannibalism. Taylor mentions that 75 species of mammals practice cannibalism. He describes how a cat may start eating some of its kittens the moment they are born. Cannibalism is not "widespread" (as he writes) because only 1500 species practice it out of millions, but it is a more widespread strategy for survival than modern humans would like to admit, especially among primates like chimps and... humans. Early cannibals did not eat human meat because they lacked alternatives: there were cannibals in the Pacific islands that had plenty of fish to eat. The early cannibals obviously had no moral obstacle to killing and eating people from other tribes, that were viewed as animals: if you don't speak my language, and have weird customs, and smell bad and so forth, my instinct is to view you as a different "species" altogether. The modern world has (hopefully) learned to respect all languages and all customs, but that was not true just a few centuries (decades?) ago. We also have evidence that, in older times, the grandfather would encourage the grandchildren to eat his/her dying body: why waste a nutritious body that would have rotten away? It made perfect sense. I suggest that humans were eating their own children too, just like the cat that gives birth to too many. In fact, that was the easiest and safest meal of all: eat your own (metaphorical) flesh. However, the human investment in children is so colossal (it takes nine months and usually you get only one) that this practice rapidly shifted to other people's children. Those were easy targets too, and, again, they were not considered the same species (tribe). It also had the additional advantage that you would remove a competitor from the great game of natural selection. Domestication of animals changed all of this because humans were the most difficult to kill: why risk your life killing humans when you can get the same proteins from a peaceful cow or goat? Taylor describes the evidence but somehow does not want to connect the dots.

Back to the main narrative, there is a problem with big brains: they should be physically impossible. Taylor travels back to the emergence of the first visible feature of human behavior: bipedalism. (After the publication of this book, an international team discovered that chimps walk upright when carrying scarce resources and suggested that humans may have started walking upright for the same reason: "Chimpanzee carrying behaviour and the origins of human bipedality). As a consequence of standing upright, bipedal beings have a smaller pelvis, and therefore a larger head for babies makes no sense. The chances of miscarriage increase dramatically. Therefore the babies with large heads should have been eliminated by natural selection. For a while our bipedal ancestors continued to have small heads, as one would expect, but then suddenly hominids began to develop large heads, and that sounds like a physical impossibility.

It gets worse. Human babies are incapable of walking upright for a long time. They are in fact incapable of doing most of the things required to survive. In a sense, all human babies are born prematurely, they are extra-uterine foetuses. In fact, the brain of human babies keeps developing at lightning speed during the first year (as opposed to the brain of the chimp, that is pretty much done and ready to go at birth).

Taylor concludes that something was needed to make all of this not only possible but inevitable. Females were the first tool-makers: the need for tools to carry plant food predates the need for hunting tools; and the need for carrying their babies around probably predates both. Bipedalism created the need for carrying babies and for carrying goods, a need that other apes solve by moving on all four. Archeologists have been saying that the first tools were the tools needed for hunting and other manly activities, but a woman needs a proto-tool, a way to carry her baby around. Imagine you are a 12-yo girl who just had her first baby, and human babies are totally incapable of doing anything, and you are not even strong enough to carry food: how are you going to carry your baby (and probably one every year) safely and quickly from A to B? You cannot afford to wait for the baby to learn how to walk. Women were constantly on the move, looking for food, carrying water, looking for firewood, etc. There were no kindergarten: they had to carry their babies with them all the time. In every single culture women have solvd this problem in the same way: every single culture developed tools to carry babies (all the way to the stroller). Because most archeologists were male, they kept thinking of hunting, but the first tools were probably made by women who were the ones who had the mother of all problems to solve: protect your babies. Otherwise all those distinguished male archeologists would never have existed! And second were probably containers (to gather and carry food). The first tools were probably invented by women, not by men, and those first tools triggered the expansion of the human brain.

The brain of human babies is still so plastic that it can absorb whatever technology is available in a way that no other species can. Other species are condemned to use the brain they get at birth, whereas human children can adapt their brain to the civilization they find. Once invented, a tool can last forever, passed by one generation to the next one simply by exposing the new-born babies to it.

Brain size started increasing, according to Taylor, after technology happened. And bodies started getting weaker because technology made it unnecessary to be strong and big. Taylor speculates that the rapid growth of the human brain was due to competition for technological supremacy. And it all started with the baby-carrying sling.

It is not intelligence that gave us tools because the earliest tools predate the rapid expansion of the brain that led to modern hominids. Brains began to grow in size after (not before) the first tools were invented. Tools made possible larger brains. Tools made possible intelligence.

Taylor also advances a theory about the first symbolic art: he thinks that ancient statuettes were the equivalent of today's mannequins in department stores (they were meant to exhibit clothes); and he thinks that cave paintings were meant to express the belief in divine creation, a rational consequence of knowing that someone makes something therefore someone must have made us. Whatever the original purpose, the beginning of symbolic art (40000 years ago) also marks the moment when human brains started "outsourcing" intelligence to our tools. Taylor claims that it also accounts for the reason that human brains have stopped expanding since that age: the need for brains decreases as technology gets smarter.

Technology has become the main driver of human evolution. We are our technology. Humans increasingly depend on technology. Technological change is accelerating. Eventually machines might get so smart that humans will not be able to comprehend them anymore. Ray Kurzweil termed it the "singularity". That singularity will allow humans to extend not only human intelligence but also the life expectancy of humans because it will overcome the material constraint of the human body in the form of artificial intelligences and avatars. Whether we will reach that singularity or not, Kurzweil starts the process leading to it from very recently. Taylor does something similar but places it at the very beginning of the evolution of Homo Sapiens: there would be no Homo Sapiens without that symbiosis between body and tools, between biology and technology. The life expectancy of Homo Sapiens would have been virtually zero because of the material limitations of the human body. The futuristic visions of people like Ray Kurzweil are actually naive: they assume that this will happen in the future, when in fact it has already happened, and it has always been the case. Both mentally and physically humans have been shaped by technology.

Plenty of biologists have recognized the importance of the "extended phenotype", of the fact that the body of a biological organism can be complemented (and usually is complemented) by artifacts, from the web of spiders (without which the spider would not exist) to the nest of birds. However, Taylor points out that human technology is of a different nature: it evolves. Spiders make the same webs they used to make millions of years ago. Humans make tools that are different from the tools of just a few years ago.

The book has plenty of interesting opinions and data, and is a "must read" for anyone interested in the origin of human intelligence. On the downside, Taylor's narrative is a bit frustrating because the real stuff is diluted in personal recollections (as it is often the case when the author or the publisher needs the spread a thin material over a book of at least 200 pages). Sometimes the thread is rudely interrupted to tell a story of hiking somewhere and then never truly restarted. Taylor asks interesting questions like "Why did we start walking upright?", "Why walking upright led to larger brains?" and "Why did it take 160000 years for Homo Sapiens to start making symbolic art?". If he answered those questions, i missed the explanations. By the end of the book, i am not sure what the conclusions are: the last three chapters are particularly confusing. I would have preferred a more straightfoward and linear scientific book without all the narrative and philosophical detours (that tend not to age too well, as he will find out).

TM, ®, Copyright © 2012 Piero Scaruffi