快猫短视频

Archaeologist and anthropologist Timothy Taylor explains how a long-vanished artefact explains human evolution and led to 鈥渟urvival of the weakest鈥�

You begin your book The Artificial Ape by claiming that Darwin was wrong. In what way?

Darwin is one of my heroes, but I believe he was wrong in seeing human evolution as a result of the same processes that account for other evolution in the biological world 鈥� especially when it comes to the size of our cranium.

Darwin had to put large cranial size down to sexual selection, arguing that women found brainy men sexy. But biomechanical factors make this untenable. I call this the smart biped paradox: once you are an upright ape, all natural selection pressures should be in favour of retaining a small cranium. That鈥檚 because walking upright means having a narrower pelvis, capping babies鈥� head size, and a shorter digestive tract, making it harder to support big, energy-hungry brains. Clearly our big brains did evolve, but I think Darwin had the wrong mechanism. I believe it was technology. We were never fully biological entities. We are and always have been artificial apes.

鈥淲e were never fully biological entities. We are and always have been artificial apes鈥�

So you are saying that technology came before humans?

The archaeological record shows chipped stone tool technologies earlier than 2.5 million years ago. That鈥檚 the smoking gun. The oldest fossil specimen of the genus Homo is at most 2.2 million years old. That鈥檚 a gap of more than 300,000 years 鈥� more than the total length of time that Homo sapiens has been on the planet. This suggests that earlier hominins called australopithecines were responsible for the stone tools.

What were these tools used for?

Upright female hominins walking the savannah had a real problem: their babies couldn鈥檛 cling to them the way a chimp baby could cling to its mother. Carrying an infant would have been the highest drain on energy for a hominin female 鈥� higher than lactation. So what did they do? I believe they figured out how to carry their newborns using a loop of animal viscera. Evidence of the slings hasn鈥檛 survived, but in the same way that we infer lungs and organs from the bones of fossils that survive, it is from the stone tools that we can infer the bits that don鈥檛 last: things made from sinew, wood, leather and grasses.

How did the slings shape our evolution?

Once you have slings to carry babies, you have broken a glass ceiling 鈥� it doesn鈥檛 matter whether the infant is helpless for a day, a month or a year. You can have ever more helpless young and that, as far as I can see, is how encephalisation took place in the genus Homo. We used technology to turn ourselves into kangaroos. Our children are born more and more underdeveloped because they can continue to develop outside the womb 鈥� they become an extra-uterine fetus in the sling. This means their heads can continue to grow after birth, solving the smart biped paradox. In that sense technology comes before the ascent to Homo. Our brain expansion only really took off half a million years after the first stone tools.

You write in the book that this led to a 鈥渟urvival of the weakest鈥�. What does this mean?

Technology allows us to accumulate biological deficits: we lost our sharp fingernails because we had cutting tools, we lost our heavy jaw musculature thanks to stone tools. These changes reduced our basic aggression, increased manual dexterity and made males and females more similar. Biological deficits continue today. For example, modern human eyesight is on average worse than that of humans 10,000 years ago.

Over the last 30,000 years there has been an overall decrease in brain size and the trend seems to be continuing. That鈥檚 because we can outsource our intelligence. I don鈥檛 need to remember as much as a Neanderthal because I have a computer. I don鈥檛 need such a dangerous and expensive-to-maintain biology any more. I would argue that humans are going to continue to get less biologically intelligent.