After humans have tried playing Doom in virtually every imaginable way, it was only a matter of time before new players stepped in. In a peculiar experiment, rats learned how to move through levels and even shoot demons inside the legendary FPS.

There is a long-standing constant in video game culture: if an electronic device has a screen, someone will eventually find a way to run Doom on it. The 1993 action classic has become both a legend and a running joke, having been successfully launched on everything from PDAs and toasters to satellites.

This time, however, an experiment moved beyond human players and handed demon-slaying duties over to rodents. Neuroengineer Viktor Tóth, who describes himself as a “gaming rat trainer,” began exploring in 2021 how non-human brains perceive and interact with virtual environments. His study involved three eight-month-old rats, fittingly named John, Carmack, and Tom, with the entire process carefully documented on his personal website.

The inclusion of video games came about almost by accident. Tóth selected Doom because of its straightforward rules and clear visual feedback. In the early stages of the experiment, a ball acted as a makeshift “controller” that the rat could move, with those movements translated directly to the in-game character. When the animal performed desirable actions, such as discovering new areas or navigating corners correctly, it received a small reward of sugar water.

Over time, the rats began to recognize when they were acting correctly. If they collided with walls, they were given a gentle puff of air to the snout as feedback. Once movement and exploration were reliably guided, the experiment progressed further. With a new setup that included touch-based controls, the rodents were also able to shoot. When a demon appeared on screen, the rig slightly lifted the rat, allowing it to trigger a sensor with its head and fire a shot.

For now, the experiment primarily demonstrates that rats can be trained to interact with virtual spaces. Whether they truly understand which game they are playing, the purpose behind it, or the underlying rules, remains an open question.

Source: 3djuegos