Researchers at the University of Reading have demonstrated that non-living hydrogels can play the video game Pong and improve their performance over time, potentially opening new avenues for simple, memory-capable materials in computing and artificial intelligence.
In a groundbreaking study published on August 23, in the journal Cell Reports Physical Science, a team of scientists has shown that hydrogels - jelly-like polymers - can not only play the classic video game Pong but also get better at it with practice.
Vincent Strong, the study's first author and a robotics engineer at the University of Reading, explained the significance of their findings: "Ionic hydrogels can achieve the same kind of memory mechanics as more complex neural networks. We showed that hydrogels are not only able to play Pong; they can actually get better at it over time."
The research team, led by biomedical engineer Yoshikatsu Hayashi, connected hydrogels to a virtual game environment using electrodes. They then established a feedback loop between the hydrogel's paddle - represented by the distribution of charged particles within the gel - and the ball's position, which was encoded by electrical stimulation.
As the hydrogel played multiple games of Pong, the researchers observed a remarkable improvement in its performance. With more experience, the hydrogel's accuracy increased by up to 10%, resulting in longer rallies. This improvement demonstrates the material's ability to use a form of "memory" to update its understanding of the environment.
The key to this memory-like behaviour lies in the hydrogel's structure and response to electrical stimulation. When stimulated, ions within the hydrogel move, dragging water molecules with them and causing temporary shape changes. Strong elaborated on this process: "The rate at which the hydrogel de-swells takes much longer than the time it takes for it to swell in the first place, meaning that the ions' next motion is influenced by its previous motion, which is sort of like memory occurring."
Interestingly, while brain cells in a dish have been shown to learn Pong in about 10 minutes, the hydrogel took approximately 20 minutes to reach its maximum potential.
The researchers believe that hydrogels represent a different kind of "intelligence" that could lead to the development of new, simpler algorithms. This is particularly significant given that most existing AI algorithms are derived from neural networks.
William Holderbaum, a co-author of the study, outlined their future research plans: "In our follow-up projects, we are thinking about how to extract the algorithm from the hydrogels that allows memory acquisition."
While the team has demonstrated that memory emerges within the hydrogels, they are cautious about claiming that the materials can truly "learn." Strong emphasised that more research is needed to definitively show that learning is occurring.
This innovative research not only showcases the unexpected capabilities of non-living materials but also opens up new possibilities for developing simple, memory-capable systems.