Basic memory allows a blob of jelly to play Pong

Inanimate blobs of ion-laden jelly can play computer games Pong And it will continue to improve over time: The researchers are planning further experiments to see if it can handle more complex calculations, and hope that it could eventually be used to control robots.

Inspired by past research into playing with brain cells in a dish Pong, Vincent Strong So he and his colleagues at the University of Reading in the UK decided to try a tennis-like game with simpler materials. They mixed ions into a water-filled polymer material so that it responded to electrical stimuli. When an electric current was passed through the material, those ions migrated to the current source, dragging water with them and causing the gel to swell.

In their experiments, the researchers used a standard computer to Pong They then used a 3 x 3 electrode grid to send electric currents to different points in the hydrogel to simulate ball movement, while a second electrode grid measured the concentration of ions in the hydrogel, which a computer interpreted as instructions for where to move the paddle.

The researchers found that not only was the hydrogel playable, but that with practice, accuracy improved by up to 10 percent and rallies also lasted longer.

The hydrogel expands faster than it contracts, and expands more slowly even when a constant electric current is applied.These properties allow the gel to record signals of expansion, creating a sort of rudimentary memory, the researchers say.

“Instead of just knowing what happened moment by moment, it's remembering the movement of the ball throughout the entire game,” Strong said, “so it's not just experiencing where the ball is right now, but the entire movement of the ball. It's like a black-box neural network that remembers how the ball behaves, how it moves, what it's doing.”

Strong said that while the hydrogel is much simpler than neurons in the brain, experiments have shown it can perform similar tasks. He believes the hydrogel could be used to develop new algorithms that would allow regular computers to perform tasks with minimal resources, making problem solving more efficient. But the hydrogel could also become an analog computer itself.

“I wouldn't rule out putting something like a hydrogel inside a robot brain,” Strong says. “That sounds interesting, and I'd like to see it. But the practicality of that is… I don't know yet.”