ELI5: What is machine learning?

Imagine your favorite toy is a robot dog named Sparky. Sparky is a bit silly at first, but you can teach him tricks. That's kind of like machine learning!

Instead of teaching Sparky by yelling or pushing buttons, you teach him with examples.

Let's say you want Sparky to learn to "sit". You show him lots of pictures:

• Picture 1: Dog sitting. You say "Sit!" and give him a treat.
• Picture 2: Dog standing. You say "Not Sit!".
• Picture 3: Dog sitting. You say "Sit!" and give him a treat.

That's what machine learning is:

• Giving a computer (like Sparky's brain) lots of examples.
• The computer finds patterns in the examples.
• Then, the computer can use those patterns to make predictions about new things.

• Netflix uses machine learning to suggest movies you might like. They look at what you've watched before (the examples) and find patterns to guess what you'll enjoy next.
• Email spam filters use machine learning to recognize spam. They've seen lots of spam emails (examples) and learned to identify words and phrases that are usually spam.
• Voice assistants like Siri or Alexa use machine learning to understand what you say. They've heard lots of people talking (examples) and learned to turn sounds into words.
• Self-driving cars use machine learning to recognize objects like stop signs and pedestrians. They've seen tons of pictures and videos (examples) and learned what each object looks like.