The Map That Grew

Uncle Dev took a corner without looking at the little glowing map on the dashboard, and Maya noticed he had switched it off.

"You turned it off," she said.

"Can't use it," Dev said. "Not for the Knowledge. They test you without it. I have to carry the whole city in here." He tapped his temple with one finger.

Soren leaned forward between the front seats. "The whole city. How many streets is that?"

"Twenty-five thousand, give or take. Plus everything on them. Every hospital, every theatre, every statue of every dead general." Dev laughed. "Ask me to take you from the Savoy to the London Eye. Go on."

"Savoy to the London Eye," said Maya.

Dev answered before she finished saying it. Left here, then this road, then that bridge, the names pouring out in a smooth river with no gaps where a map would go. Maya watched his eyes in the mirror. They were not searching for anything. The answer was just there, the way her own name was just there.

"That's three years of studying," Dev said. "On a little scooter, in the rain, learning every road. Most people fail it twice before they pass."

Soren had his notebook open on his knee. He drew a small lopsided shape and frowned at it.

"What's that," said Maya.

"It's supposed to be a brain. There's a part shaped like a seahorse. Hippocampus. It does maps, I think. Where you are, where things are." He tapped the page. "I read that the taxi drivers here, their seahorse part is bigger. They measured it."

Maya turned all the way around in her seat. "Bigger than what?"

"Bigger than other people's. And bigger than it was before they studied. The longer someone drives, the bigger it gets."

"Wait." Maya held up a hand. "You're saying his brain is a different shape than mine because of streets."

"That's what the scan showed. The back part of the seahorse, the part that holds where-things-are, it grows."

Dev glanced in the mirror. "My missus says my head's gotten big. Maybe she's right and I owe her an apology."

Maya wasn't laughing. She was looking at the back of her uncle's head as though she could see through it.

"It grows," she said slowly. "Like a muscle."

"Not exactly a muscle," Soren said. "A muscle gets stronger. This is more like, the brain builds more brain. New connections. More gray matter, in the spot that needs it."

"So if you do a thing for three years," Maya said, "the meat changes shape to fit the thing."

Soren looked up from the notebook. "Yeah. That's actually exactly it."

They both went quiet. Dev took another corner he could not possibly see coming.

"Try this one," Maya said. "Liverpool Street to the zoo."

The river of street names came again. Maya wasn't listening to the names this time. She was listening to the speed, the no-gap smoothness of it, and trying to imagine what shape made that sound.

"Uncle Dev," she said. "When you started. The very first week. Was it like this?"

"God, no." He snorted. "First week I got lost going to the depot. I'd look at the map fifty times and it'd fall straight out my head. I cried in a car park once, if you want the truth. Thought I wasn't built for it."

"But you were the same person," Maya said. "Same head."

"Same head, love."

"No," she said. "That's the thing. It wasn't the same head. It was a smaller seahorse." She turned to Soren. "He wasn't built for it. He built himself for it. The crying-in-the-car-park him didn't have the brain yet. He grew it by failing at it over and over."

Soren stopped drawing. "The failing is the building," he said. "Every time he got lost and had to fix it, that was the part adding more of itself."

"So getting it wrong fifty times isn't the opposite of learning," Maya said. "It's the actual learning. It's the bricks." "There's a catch," Soren said. "I read that part too. When taxi drivers retire, when they stop using the map, the seahorse shrinks back down. Toward normal."

Maya's face did something complicated. "It can get smaller again?"

"If you stop. The brain doesn't keep what you stop using. It gives that space to something else."

"So it's not a trophy," Maya said. "It's not like, you win the big brain and keep it on a shelf." She pressed her thumbnail into the seat. "You're renting it. From yourself. The whole time."

"Huh," said Soren. He wrote that down, the pen moving fast.

Dev pulled up at a red light and finally spoke. "You're telling me," he said, "that the worst part. The three years of feeling thick and lost and like everyone else got it but me. You're telling me that was the part that was working."

"That was the only part that could work," Maya said. "The map didn't go in because you were clever. It went in because you kept being wrong at it until your head changed shape."

The light went green. Dev didn't move for a second. A taxi behind them beeped.

"Three years," he said again, more to himself, and pulled away.

Maya turned to Soren in the back seat. "Do the maths thing you do," she said. "You hate maths. You said it falls out of your head."

"It does. Every time."

"Every time you do it and it falls out and you do it again," she said, and she was almost vibrating now, "that's the car park. That's the scooter in the rain. You're not bad at it. You're early in it. There's a bigger-seahorse you that hasn't been grown yet."

Soren looked at his lopsided drawing of the brain. He started adding to it, lines branching off the little seahorse, more and more of them, filling the space.

"How big can it get," he said quietly. Not to Maya. Not to Dev. To the drawing.

In the front, Uncle Dev named the next four turns to nobody at all, just to feel the river of them come, and his eyes in the mirror were not searching for anything.