The Robot That Only Knew Cats
Bolt learned what a cat was from four hundred pictures. Then a dog walked in. A story about why the examples you show a computer matter more than the computer does.
Bolt was a very small robot with one job: say what things are.
To teach Bolt, you showed him pictures. Lots of them. Hundreds. Every time you showed him a picture you also told him the answer, and Bolt wrote down what he noticed.
Nell taught him cats first, because she had a cat, and because taking four hundred photographs of your own cat is an excellent way to spend a Saturday.
Picture one: Marmalade on the sofa. "Cat," said Nell.
Picture forty: Marmalade in a box. "Cat."
Picture two hundred and six: Marmalade, upside down, being unhelpful. "Cat."
Picture four hundred: Marmalade. Obviously.
By the end Bolt was extremely confident. Pointy ears. Whiskers. Four legs. Fur. Orange. He had it. He could spot Marmalade in any room, in any light, from any angle, instantly.
Nell was delighted. She took Bolt to the park to show her friend Sam.
Sam had a dog. The dog was called Biscuit, and Biscuit came galloping over with his tongue out and his ears flapping.
Bolt looked at Biscuit for a long moment.
"Cat," said Bolt.
"No," said Nell.
"Cat," said Bolt, more firmly, because Biscuit had four legs and fur and was, in fairness, a sort of orange.
"That is a dog, Bolt."
Bolt did not know what a dog was. Nobody had ever shown him one. He had four hundred pictures in his head and every single one of them was a cat, so as far as Bolt could tell, the world contained cats and things he had never heard of, and Biscuit was clearly not the second one.
Nell sat down on the grass and thought about it.
"It is not that he is broken," she said. "It is that I only showed him one thing."
So they took four hundred pictures of Biscuit. And then, because Sam pointed out the obvious problem, four hundred pictures of a grey cat, and a black cat, and the enormous bad-tempered cat from number eleven who had to be photographed from a safe distance.
Bolt got much better.
He still got things wrong sometimes. He once confidently identified a cushion as a cat, and honestly, it was a very cat-shaped cushion.
But he never called Biscuit a cat again.
For the grown-up
Why this story is built this way
This is a story about training data, and it is deliberately not a story about a robot being stupid.
Bolt behaves correctly given his inputs. The failure is in the dataset, not the machine, and Nell reaches that conclusion herself in one line: it is not that he is broken, it is that I only showed him one thing. That sentence is the entire lesson and it is the reason the story exists.
Children who meet the concept this way have a usable frame for every bias conversation they will have later, and they got it before anyone told them it was a difficult or political subject. The cushion at the end is there on purpose too: even a well-trained system still gets things wrong, and pretending otherwise would undo the honesty the rest of the story is built on.
Do something with it
Teach the computer cats
Choose which pictures to show the computer so it learns properly, then choose one that would teach it something wrong and explain the damage.
Open the activityAsk afterward
Four questions that usually go somewhere
- Was Bolt broken, or was something else wrong?
- What would you have shown him first?
- What else could Bolt get confused about?
- If somebody only ever showed you one kind of thing, what might you get wrong?
Words in this one
If they ask what a word means
The books
When an idea turns out to be worth forty pages instead of two, it becomes a book, and the books live next door at DigitalCrayonBooks.com. Here is how the two sites divide the work.