The RL Spiral, Part 2: The Equation That Explains Your Brain

Every advanced AI runs on an equation. Your brain has been running it for 500 million years. A neuroscientist proved it by accident. That accident changed two fields at once.

This is the second article in The RL Spiral, an eight-part series on reinforcement learning. The first article, The Reward Trap, explored why reward specification is so hard. This one explains where the reward signal came from.