Paws on the wheel: the incredible experiment that taught rats to drive

This article was published in The Conversation under a license Creative Commons.

We made our first rodent car from a plastic cereal container. After a process of trial and error, my colleagues and I discovered that the rats could move forward by holding on to a small wire that acted as an accelerator pedal. Before long, they could drive with surprising precision to reach a prize. As expected, rats housed in enriched environments—with toys, space, and companions—learned to drive faster than those living in standard cages. This finding supported the idea that complex environments enhance neuroplasticity, the brain’s ability to change throughout life in response to environmental demands.

After we published our research, the story of rats driving vehicles went viral in the media. The project continues in my lab with new and improved rat-operated cars, or ROVs, designed by robotics professor John McManus and his students. These upgraded electric ROVs, which feature rat-proof wiring, indestructible tires, and ergonomic steering levers, are similar to a rodent version of Tesla’s Cybertruck. As a neuroscientist who advocates housing and experimenting with laboratory animals in natural habitats, I found it fun to see how far we have moved away from laboratory practices with this project. Rats often prefer dirt, sticks, and stones to plastic objects. Now, we make them drive vehicles.

Humans did not evolve to drive. Our ancestors didn’t have cars, but they had flexible brains that allowed them to acquire new skills: fire, language, stone tools, and agriculture. And some time after the invention of the wheel, humans made vehicles. Although those made for rats are nothing like what they would find in the wild, we believed that driving represented an interesting way to study how rodents acquire new skills. Unexpectedly, we found that the rats were intensely motivated for their driving lessons, often getting into the car and revving the “stick motor” before the vehicle hit the road. Our question was: why is this happening?

The new destination of joy

Concepts from introductory psychology textbooks took on a new practical dimension in our rodent driving laboratory. Based on fundamental learning approaches, such as operant conditioning, which reinforces target behavior through strategic incentives, we train the rats step by step in their driver’s education programs. At first, they learned basic moves: getting into the car and pressing a lever; But with practice, these simple actions evolved into more complex behaviors, such as driving the car to a specific destination.

The rats also taught me something profound one morning during the pandemic. It was the summer of 2020, a period marked by emotional isolation for almost everyone on the planet, even rats. When I entered the lab, I noticed something unusual: The three driver-trained rats eagerly ran to the side of the cage, jumping like my dog ​​does when I ask him if he wants to go out for a walk. Had rats always done this and I hadn’t realized? Were they eager to eat cereal or were they anticipating the moment of eating? Be that as it may, they seemed to be feeling something positive, perhaps excitement and anticipation.