Professor Alice Roberts is expecting her second child. I don't think I've ever seen anyone look so happy to be pregnant. She floats around, backlit by the sun and beaming, stroking her bump, marvelling at other babies and at the wonder of it all. Often she'll get out her sketchbook to draw some of it, the wonder. But this is not just Me and My Miracle, it's Horizon: What Makes Us Human? (BBC2). There's serious science to be done.
So she's off to meet the rellies, at Leipzig zoo. You know, bonobos, gorillas, chimps, the other great apes – 99% the same, 1% different, DNA-wise.
They are so much quicker out of the blocks. Even birth itself – they just shoot out like ferrets from a pipe. And they hit the ground running (or swinging). For us there's all that pushing and wailing and swearing by our mums. After which we just lie around helplessly, crying and pooing and not much else, before the tantrums start, which means more wailing and swearing by everyone. We're utterly useless, for years and years.
But we do overtake the other apes eventually. I mean the chimps never sketch us, do they, sequence our genome or plot our brains? Idiots. They are quite good at getting a peanut out of a tube though, quicker than Prof Roberts in fact. It's not that we're more intelligent, says this other dude, we're just intelligent in different ways. Like squirrels and birds have the best memories, for example. Never ever get involved in a game of pelmanism with a squirrel or a rook, you will lose (well, you would do if you could explain the rules of pelmanism to your opponent, they're less good at that). Chimps are excellent at understanding space and causal relationships and tasks that involve them getting a peanut at the end of it. They will even collaborate on a task if there's a peanut to be had.
Ah, but look at these kids, lovely little Kinder (we're still in Leipzig). They too will collaborate on a task, but then if their rewards aren't equal they'll share them out until they are. Little hippies. Where's their competitiveness? None of this lot is ever going to be head of Deutsche Bank, are they? They'll probably end up sponging off the generous German welfare state, which may not be so generous by then, the way things are going …
Anyway, it shows our ability to cooperate and create human culture. Which makes us different. It's all to do with our massive brains, which becomes Prof Roberts's focus. Our brains – along with our upright walking style and requisite upper limit on pelvis width – are the reason for all the fuss at childbirth, right? And why we have to come out so woefully undercooked and utterly useless. And why women are rubbish at running … boo, sexist! Also wrong – it turns out pelvis width has little to do with running ability, and babies come out not when their heads are getting too big but when they start demanding more energy than their mums can give them. There's the obstetrical dilemma sorted then, I think.
Anyway, Prof Roberts is looking at the female pelvis in a whole new light now. Looking through one too, at the Chrysler building at night (we're no longer in Leipzig). Shouldn't it be the Empire State though? Because that's the one King Kong climbed, and he was an even greater ape … or perhaps I'm reading too much into it.
It gets more complicated. She cuts a real brain into slices (ouch! You half expect to see the old memories of the donor seeping out). We're into genome sequencing, millions of letters, thousands of pages (and that's just one-fiftieth of chromosome 1). And then a 3D-wiring diagram of a brain – not a human brain, which would take four million years to map, but a tiny part of a mouse brain. It's beautiful, a mass of coloured strands twisted together, even if my own mouse brain can't quite fully understand what it all means That's OK though, the neuroscientist says it's hard for a human brain to understand the extraordinary complexity of the human brain. There's something beautiful about that too, man.
Right, time for Prof Roberts to push a new one out, through her own reconsidered pelvis. Not on TV thankfully, cut to the result. Aw … he's beautiful. Definitely not a bonobo, his head's too big, and he's too utterly useless. But he's all wired up inside his brain, ready to go. Ready to learn to become a human being.