Look at me when I'm talking to you

Since my last post I've had a couple of requests for more smart stuff about the brain. Now I have to say this is not one of my main areas of expertise. 

"What is?" Susan says, looking over my shoulder, which is something I've hated since primary school, when Miss Jamieson, as suited to teaching as I am to international diplomacy, read sneeringly aloud my fleeting ambition to be a flower-arranger.  

Jamieson had a booming voice and a chest like Ben Venue and as a seven-year-old I was equally scared of both. I never got the hang of keeping her happy. Quite the reverse. She'd be driven at times to heights of maniacal frenzy I have not encountered in my life as a grown-up. 

"Kids, women, engineering," I tell Susan.

"Ha!" she says and wanders out to the garden, which is looking lovely at this time of year. Pink roses, yellow honeysuckle, purple clementine ... I suppress my inner flower-arranger and get back to the story.

So your brain has three main parts: the cerebrum, the cerebellum and the brainstem. 

The cerebrum is the grey, wrinkly bit you see in all the brain pictures. It has two hemispheres - the northern, where most people live, and the southern which has penguins. No, hang on. 

The cerebrum has a left hemisphere and a right hemisphere. These are connected by a bundle of nerves called the corpus callosum. If a surgeon cuts this, which used to be a treatment for epilepsy, the halves can behave like two people in the same body. One guy even got stuck in a loop, with his left hand pulling his trousers down and his right pulling them up again. 

And here's a strange thing. The left hemisphere of your brain controls the right half of your body and the right controls the left. Nobody knows why. Maybe God read the wiring diagram wrong. 

But I have a better theory. 

Flatfish such as plaice and flounder have two eyes on one side of their body. They don't lie on their tummies on the seabed, as you might think, but on their sides. So as a flatfish develops, one eye migrates round to the other side of its body.

I believe something similar happens to our heads. They start off facing backwards, with brain and body halves aligned. Then nature looks down, sees heels instead of toes and realises it's cocked up again. 

So it slowly turns the whole head around. The face is now in the right place but the brain is back to front, relative to the body.

Now you might think this is a stupid theory. I'm pretty sure you do. But plenty of seemingly stupid science theories turn out to be true. Time travel, quantum mechanics and evolution, for a start.

And I have evidence to support my theory. When I worked at British Aerospace my section head Dennis Anderson told me a story about the manager director, whose mum he knew well. When this guy was born they got a big fright, she'd told Dennis, because he seemed to have no face.

"It was a terrible shock," Dennis said. "Then the midwife took a closer look and found the face. What a relief! It was round the side of his head. Over the next week it gradually migrated to the front and he's been normal ever since. In fact, he's a high-flyer, as you know."

Now babies' skull bones are malleable and a tough birth can squeeze them out of shape for a while. My own head was squished pretty flat when I was born. There was some talk of sending me home by post, to save money, and getting me popped through the letter-box. But my mum didn't have a stamp so we had to go on the bus. 

A face right round the side of the head is different though, and I think it's strong evidence for my theory. 

"What theory is that?" Susan says, coming in from the garden with a bunch of pink roses and reading over my shoulder again.

"The human face starts out at the back of the head," I tell her. 

"Yours should have stayed there," she says, heading through to the kitchen to find a flower-vase and laughing like a drain.

Did meat make you smart?

Before relating this week's encounter, I need to slip you some skinny on the human brain. 

Mine weighs about 1.5 kilograms. Yours might be a little more, because I'm guessing you didn't superglue your index finger to your thumb yesterday.

"Be careful," Susan tells me, as I'm dripping liquid UHU onto a plastic doofer I've shaped to fit into a rough-edged hole inside the drum of her washing-machine that's tearing her clothes every time she does a washing. "Superglue can be dangerous."

"Give me some credit," I say. "Do you know how long I've been using tools? Have you any idea how much skill has seeped into these fingers? Can you imagine the depths of knowledge ... Oops."

"What have you done," she says, with that long-suffering drop in intonation I often hear at the end of women's sentences when they talk to me.

I raise my left hand, which looks like I'm doing a shadow-puppet goose.

"Do not," she says. "Move a muscle. I'll google what to do next."

But I reckon time is short. So surreptitiously I start to pull finger and thumb apart, testing the relative breaking strengths of the new superglue bond and my old outer layer of skin. Sensitive to small clues others might miss, my finely-honed engineer's brain tells me the former is weaker, so I exert a greater force.

"'Do NOT try to pull finger and thumb apart,'" Susan reads from her computer. 

"Aaagh!" I squeal.

"Pillock," she says.

So Carol's theory, which she explains to me in the garden at little Sally's second birthday party, is that the brains of seabirds are evolving so fast they will soon be the dominant species on Earth.

"They've moved inland to live off humans," she says. "So they're getting more protein than ever before. That's what gave human brains a big boost, back in our days on the African Savannah. 

"You remember them?" she adds, unnecessarily.

"And here's the thing," she continues, indicating two yellow-eyed herring gulls perched on the back fence, coveting their neighbour's birthday cake. "When those buggers rule the world, it's going to be Hell. You know why? They're Nazis."

This seems over the top to me. Did gulls annex the Sudetenland? Hardly. Did they invade Poland when I wasn't looking? I don't think so. "They are just birds trying to earn a crust," I tell her.

"No they're not," she says. "They're evil. They'll be goose-stepping around in jackboots any day now. They'll enslave all humans and conduct fiendish experiments on us."

"No they won't," I tell her and I'm pretty sure I'm right. See, here's the thing about young Carol. She is prone to hyperbole for humorous effect. But study the content of her conversation, no matter how far-fetched, and there's usually some interesting truth in it. 

So when I got home I looked this one up. And it turns out there's science behind what she was saying.

Now I'm not telling you seagulls are going to drop bombs on London. Nor that we will have to fight them on the beaches. Far less that there's a little corporal seagull with a black moustache somewhere, writing a manifesto for world domination.

The science is about how humans got big brains. It's called the expensive tissue hypothesis and it goes back to a 1995 scientific paper by Aiello and Wheeler. For the full story you'll need to go to our smart sister site, Three Minute Learning. 

The basic idea is that big brains need lots of energy. But humans burn only about the same as other apes of similar body weight. How can that be?

We do it by saving energy on another expensive organ, said Aiello and Wheeler - our guts. Long intestines are needed to digest vegetation. Short ones do meat. Human guts are shorter than those of other apes. So our ancestors' brains were able to grow as a direct result of eating more meat which let them have shorter guts.

This paper was bad news for vegetarians. The carnivores now had a scientific stick to beat us with. "Meat made us smart" crowed the Mail and Sun, contradicting the evidence on every page. 

But here's the thing about science. Like a man on hot coals it never stands still. In 2011 a bunch of Zurich scientists made Swiss cheese of the smart meat story, by punching big holes in it. 

If the expensive tissue hypothesis were true, animals with bigger brains should have smaller intestines, said Ana Navarrete and her colleagues. So they studied the organs of 100 mammal species and found no trace of that correlation. 

But this left a fact without an explanation. Humans and apes of the same weight burn the same amount of energy. But human brains need more energy than ape brains. Where was it coming from?  

Energy efficiency from walking on two legs was part of the answer, said Navarrete. The other is that humans carry more fat than the rest of the apes. Compare lean body weight rather than total and we humans are burning more energy than other apes.

So not only was the expensive tissue hypothesis disproved. There was no need for it in the first place. 

So nice try Carol and bad luck seagulls. But I'm wondering if evolution is all it's cracked up to be.

When did you last see a gorilla superglue its index finger to its thumb?

Sweet scents in the afternoon

My reaction is all wrong. I know it is. I shouldn't be so prejudiced. But it all goes back to Jim Girvan, my best pal in primary school. 

I made the mistake of telling Jim, when we were about 10, that I fancied going to university to become a scientist. I hadn't a clue what a university was, or a scientist come to that. But I'd discovered a dusty, blue-bound book in my Aunt Mary's attic in Kirkcaldy. It had glossy black-and-white photos of spiral galaxies and far distant nebulae.

The size and beauty of the universe took my breath away. It really did. I forgot to breathe for half a minute, then I gasped. The book was called The Marvels and Mysteries of the Universe. My Aunt Mary said I could keep it. That made me happy.

But it horrified Jim. "If you go to university you'll get posh and never speak to your old pals again," he said. 

I assured him no such thing would happen, but our friendship was never relaxed after that. I tried too hard not to be posh around him and it made me stiff and uncomfortable.

I'm still trying. I can feel him in there now, disapproving. Which is why I'm less enthusiastic about the new supermarket than young Rachel. "It's a better form of business," she says, as we pass the adverts for Barbour jackets and cello tutors. "There's no shareholders and the staff get a share of the profits. And they treat farmers better than other supermarkets."

"Ah ha!" I say. "That's your ethical system right there, isn't it? What's good for farmers is good, period. That's because you're a farmer's wife. I'm not so keen on farmers. They pollute the atmosphere."

"You don't half talk shit," she says.

"Precisely," I say. "We had farmers' sons in our class, Jim and me. Sweet scents wafted off them in the afternoon. 'A fine healthy smell,' they'd tell us. But it wasn't. It was cowshit. Or maybe horseshit. I'm not a shit expert."

"You're a shit judge of shops," she says. "This one's lovely.

"Yeah, if you like buttercup petal tea," I tell her. "Or yak's milk cheese. Or quails' eggs dipped in dark chocolate, with a hint of mint. 

"Look at this!" I shout, picking up a long, thin can with a sea-green label, and getting a sharp glance from a couple of blondes of uncertain age and eyebrows. 'Octopus testicles.' That's appalling. What kind of pervert eats octopus testicles?"

She takes the tin off me and reads the label. "Tentacles, you fool," she says. "Octopus tentacles."

"That's just as bad," I say. "Poor old octopus."

"Listen, I know what you'll like," she says. "It's very satisfying."

"What?" I say.

"Charlie's marmalade."

"That's some kind of euphemism, isn't it?" I say. "'Let's invite the neighbours around for a spot of Charlie's marmalade.' I think it's disgusting what you people get up to."

"Put a sock in it," she says, taking a jar off the shelf and pointing to the label. 'Duchy Originals, thick cut orange marmalade.' That's the company Prince Charles founded."

I take a look. "Read the rest," I tell her.

"Rich bittersweet marmalade made with fine Seville oranges, hand-stirred in open pans for a chunky texture and robust flavour," she reads. 

"Would you like a slice of toast and mahmalade, my deah?" I say, in my southern stupid voice. "It's hand-stirred in open pans for a chunky texture and robust flavour."

I shake my head. "I got to get away from here."

Outside in the car-park I sit sadly on the fence and look at the sky. Blue all over with a little fluffy job in one corner and the sun in the other. A blackbird trills in a nearby sycamore. It's kinda peaceful.

Rachel walks across the tarmac and sits beside me, annoyance all gone. "Listen pal, I bet Jim Girvan lives in Bearsden now, drives a four by four, grows aubergines in his garden and has beautiful vowels." 

She pats me on the head sympathetically. "It was a long time ago," she says. "You're middle class now. It's all right. Honest it is."

I am not convinced. And I hate it when posh people pat you on the head. I really do.