ELI5: what is neural network

A neural network is like a smart system that learns to do things by looking at lots of examples, just like you learn to recognize your favorite toy by seeing it many times.

Imagine you want to teach a computer to recognize pictures of cats. A neural network can do this! Think of it like this:

• The network has lots of little helpers (neurons). Each helper looks for specific things in the picture, like pointy ears, whiskers, or a furry tail.
• You show the network tons of cat pictures (training data).
• Each helper tries to guess if it's seeing a cat. If it's wrong, you tell it to adjust how important its thing (ears, whiskers, etc.) is.
• Some helpers might learn that pointy ears are very important for identifying cats. Others might learn that the color of the cat doesn't matter much.
• After seeing many pictures, the helpers get really good at working together to decide if a new picture is a cat or not.

• At first, you wobble and fall a lot. Your brain is like a neural network, trying to figure out the right balance and steering.
• Each time you wobble, your brain adjusts a little bit – you lean slightly to the left, or you pedal a little faster.
• After many tries, you learn to balance and steer automatically. Your brain has learned the "rules" of riding a bike through practice and adjustment.

• Your phone uses them to recognize your face to unlock it.
• Streaming services use them to recommend movies and shows you might like.
• Smart speakers use them to understand what you say.
• Self-driving cars use them to see the road and avoid obstacles.