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How the bones got there

What were our female ancestors doing when the men were hunting? Did they not contribute to evolution at all?
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First Published: Thu, Jan 03 2013. 07 01 PM IST
A file photo of a Bonobo. Photo: Wikimedia Commons
A file photo of a Bonobo. Photo: Wikimedia Commons
Updated: Thu, Jan 03 2013. 07 24 PM IST
In recent weeks I’ve been thinking about men assaulting folks with rods. You don’t need me to tell you why.
Now there was a time, only two or three generations ago, when scientists saw our ancestors as brutal killer apes. We owe this theory to the Australian archaeologist Raymond Dart, who based it essentially on what he found at one site in South Africa: human-like and other animal bones, 42 crushed baboon skulls, and many tools.
With this much, Dart suggested that our ancestors used to batter victims to death with clubs. From that violent past, we evolved to who we are today. (Yes, the scum on the Delhi bus too.)
“Man the Killer Ape” fits the ghastly images from that bus. It also fit humankind’s mood in the wake of the slaughter of two World Wars. But like humans themselves, that theory evolved.
Came the 1960s, and the popular wisdom was that our ancestors had been hunters. Early man roaming the plains of Africa, taking down dangerous animals, carrying hunks of meat home to feed women and children: this seductive vision drove anthropological thinking then. It also matched how we saw ourselves then—fearless explorers reaching for the moon and stars.
But “Man the Hunter” failed to explain something vital. Hunting was a male activity. Why should our species’ evolution—meaning females too—be driven by what males alone did? After all, women’s brains today are just as large as men’s. What were our female ancestors doing when the men were hunting? Did they not contribute to evolution at all? Were females really just insignificant evolutionary players?
In the 1970s, a whole new theory answered that. According to feminist anthropologists, the life of early humans revolved around mothers and children. Females gathered eggs, roots, honey and nuts, developing the tools they needed. They shared this food with the family. This was their main source of nutrition. And what of hunting? Secondary at best, because it never brought in a steady supply of food.
So rather than hunting by males, it was gathering by females that drove human evolution: a theory that went well with the feminist temper of the 1970s.
But it brought more questions. If we replace a bias for one sex with a bias for the other, do we better understand our origins? If “Man the Hunter” did not satisfactorily explain human intelligence, how could “Woman the Gatherer” do so?
Answer, it doesn’t. Here’s the thing: Our ideas of the past are coloured by our view of the present.
For example, some palaeontologists were struck by the near-perfect symmetry of stone “axes” found in prehistoric sites. When attached to a wooden handle, they suggested, the symmetry makes the axe easier to balance and wield: that’s why the symmetry.
A thoroughly sensible hypothesis; but also a thoroughly modern one.
We know that modern axes have such handles, and would benefit from such symmetry. But nothing tells us that primitive axes had them. Of course, any handles they might have had would have disintegrated over the millennia. But the point is that we have no evidence of them. The reason palaeontologists remark on the symmetry is that they know about modern axes. By itself, the primitive “axe” says little: not even that it is an axe at all.
The lesson? The primary task of a scientist trying to explain evidence is to identify, understand and discard what he does not know to be true, even if it is plausible. What’s left might be nothing at all. On the other hand, it might be a stronger, truer theory.
With artifacts from a distant past, this gives us what the late Lewis Binford, an argumentative, unpopular but influential archaeologist at the University of Chicago (and elsewhere) used to say: we cannot assume that everything found close to obviously human artifacts is, therefore, a result of human activity.
For example, the “Killer Ape” theory drew on artifacts, including crushed skulls, found at one site. Dart assumed our ancestors had killed the baboons. But Binford would ask: Why should we assume it happened that way? There are other ways these bones might have come together. They might have been brought there by a stream, or collected by other carnivores. In fact, a later study showed that it was possible that a leopard, sitting in a tree and feeding on both baboons and ancient men, had dropped the bones. Looks like the Killer Ape had been among the eaten.
So does this mean Dart’s theory, and others that followed, are worthless? Not at all. Each teaches us new techniques, tells us more about our origins. Most important, each rids us of more of our ignorance. We may never fully understand how our ancestors lived. But we’ll get closer all the time. We’ll learn a lot about ourselves.
“The question ‘Is this true?’ doesn’t lead anywhere,” Binford once said. “The question to ask is, ‘Does this open up new learning opportunities?’”
Once a computer scientist, Dilip D’Souza now lives in Mumbai and writes for his dinners. A Matter of Numbers will explore the joy of mathematics, with occasional forays into other sciences. To read Dilip D’Souza’s previous columns, go to www.livemint.com/dilipdsouza-
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First Published: Thu, Jan 03 2013. 07 01 PM IST