ELI5: what is deep learning

Deep learning is like teaching a computer to learn from examples, just like you learn by seeing and doing things many times.

Imagine you're teaching your little brother to recognize cats. Instead of telling him exactly what a cat is (furry, pointy ears, whiskers), you show him lots and lots of pictures of cats.

• First, you show him some pictures. He might guess randomly at first.
• Then, you tell him whether he's right or wrong. "Yes, that's a cat!" or "No, that's a dog!"
• He slowly starts to notice patterns. Maybe he notices pointy ears are important.

• The first layer looks at the picture (or sound, or text).
• Each layer tries to find simple patterns (like edges, colors, or sounds).
• Later layers combine those simple patterns into more complex things (like ears, eyes, or words).
• The last layer makes a guess: "Cat!" or "Not Cat!"

You see deep learning at work every day:

• When your phone recognizes your face to unlock.
• When Google Translate helps you understand a different language.
• When Netflix suggests movies you might like.
• When your email filters out spam.