Brain Cells Playing Doom: How a Dish of Human Cells Learned a Game

Full transcript

Human brain cells in a dish are playing a game called Doom.

About two hundred thousand of them, grown in a lab and spread across a computer chip. The chip turns the game into tiny electric pulses, and turns the cells' replies into moves.

So how do you teach a dish of cells to play a game? You cannot give a brain cell a reward. The trick is chaos. Every time the player gets hurt, the cells get blasted with random noise. When it plays well, the signal turns calm and steady. Brain cells seem to hate what they cannot predict, so they slowly change what they do to keep things calm.

That is how the same company taught cells to play Pong, a simple tennis video game, back in twenty twenty-two. Then, in twenty twenty-six, an outside programmer hooked their cells up to Doom. It took him about a week.

The Doom player was not good. It spun in circles. It wandered. It died a lot. An ordinary computer program did most of the work. But with the cells in the loop, it played better than the program on its own.

So why build it at all? Your whole brain runs on about twenty watts, less than a light bulb. The computers that run artificial intelligence use vastly more.

In its Pong paper, the company called the cells sentient, meaning able to feel. Thirty neuroscientists signed a letter saying that word went too far. A dish of cells is not a mind.

Most scientists say these cells feel nothing, but we're not sure if the cells are saying the same thing...