Let's talk about perceptrons, kids — and I promise this is way less scary than the word sounds.
Imagine a tiny robot brain whose whole job is to answer one yes-or-no question. Should I open the umbrella? Is this a cat? Should I let this email through, or send it to spam? That little robot is a perceptron, and here's the trick to how it decides: it doesn't just look at one thing, it looks at several clues at once, and it cares about some clues more than others.
Say the question is “should I go outside and play?” Your clues might be: is it raining, is it cold, and is it a school day. Each clue gets a little dial called a weight, turned up or down depending on how much that clue matters to you. Rain probably gets turned up high — you really don't want to go out in a downpour. Cold might be turned down a bit, since you can just wear a coat. The perceptron multiplies each clue by its dial setting, adds all those numbers together into one big number, and then checks: is that number big enough to cross a line in the sand?
That's it. That's the whole trick. One tiny yes/no decision, made by weighing a few clues and adding them up. The wild part is that scientists discovered if you chain thousands of these simple little yes/no robots together, layer after layer, each one looking at the answers from the robots before it, they can learn to recognize handwriting, tell a dog from a muffin, or even hold a conversation. One simple idea, stacked really really tall.