How humans and computers follow instructions

Years ago, when I taught Information technology, I used two stories to explain the difference between how computers and people followed instructions.

1. People are rubbish at following the simplest of instructions.

I'd ask the class to all point at the brainiest pupil in the room and then select that person as my victim to demonstrate. I'd bring them out in front of the class and tell them:

Teacher "I'm going to say three simple words with a pause between each word. All you have to do is repeat the word. Here's the first - Cat."

Pupil  "Cat."

Teacher "Rhino"

Pupil "Rhino"

Teacher "WRONG!"

Pupil, looking flustered "What was wrong? I said Rhino."

Teacher You failed. The third word was the word 'WRONG'.

People think about their answers - computers just do what they are told to do.

2. Computers do EXACTLY what you tell them to do.

Imagine a boy with a computer instead of a brain. he is woken up one morning and told the following by his mother.
"Run down to the shop and get a loaf of bread. Take £2 from my purse on the kitchen table. And for heavens sake - Get dressed"
The boy immediately runs to the nearest shop. It's a butcher's shop and doesn't sell bread so he waits there until someone comes in with a loaf of bread. That may take a while. Eventually a little old lady comes in with a loaf of bread in her shopping basket.
The boy wasn't told to pay for the bread so he 'gets' it. Effectively he steals it from her.
The boy wasn't told to come back but the next instruction was to get £2 from the purse on the kitchen table so he does come back.
The purse isn't on the kitchen table. it's on a work surface at the side. So he waits again for the purse to move to the table. He doesn't put the bread away because he wasn't told to do that.
When the purse is eventually on the table he tries to take £2 from it. If the purse only has five pound notes in it he is again stuck waiting.
When the boy eventually has a £2 coin only then does he get dressed.

Humans take bad instructions and correct them. They decide the best order to do them in and include missing instructions. Computers can't do that. We won't have true Artificial Intelligence until a computer can follow the second task and get it right.