I taught rats to drive, but they taught me to enjoy the ride
A neuroscientist on lessons learned from teaching rodents to drive a mini-car.
Guest column by Kelly Lambert
We crafted our first rodent car from a plastic cereal container and quickly found that rats could learn to drive forward by grasping a small wire that acted like a gas pedal. Before long, they were steering with surprising precision to reach a Froot Loop treat.
After we published our research, the story of driving rats went viral. The project continues in my lab with new, improved rat-operated vehicles, or ROVs, designed by Randolph-Macon College robotics professor John McManus and his students.
Although cars made for rats are far from anything they would encounter in the wild, we believed that driving represented an interesting way to study how rodents acquire new skills. Unexpectedly, we found that the rats had an intense motivation for their driving training — something we wanted to learn more about.
Destination: Joy
As a neuroscientist who advocates for housing and testing laboratory animals in natural habitats, I’ve found it amusing to see how far we’ve strayed from my lab practices with this project. Rats typically prefer dirt, sticks and rocks over plastic objects. Now, we had them driving cars.
But humans didn’t evolve to drive either. However, they had flexible brains that enabled them to acquire new skills.
Concepts from introductory psychology textbooks took on a new, hands-on dimension in our rodent driving laboratory. Building on foundational learning approaches such as operant conditioning, which reinforces targeted behavior through strategic incentives, we trained the rats step-by-step.
Initially, they learned basic movements, like climbing into the car and pressing a lever. But with practice, these simple actions evolved into more complex behaviors, such as steering the car toward a specific destination.
One morning during the pandemic, the rats also taught me something profound.
It was summer 2020, a period marked by isolation for almost everyone on the planet. When I walked into the lab one day, I noticed something unusual: The three driving-trained rats ran to the side of the cage, jumping up and down.
At that point, my lab started looking into how positive events — and anticipation for these events — shape neural functions.
Building anticipation
Working with postdoctoral fellow Kitty Hartvigsen, I designed a new protocol that used waiting periods to ramp up anticipation before a positive event.
Bringing Pavlovian conditioning into the mix, rats had to wait 15 minutes after a Lego block was placed in their cage before they received a Froot Loop. They also had to wait in their transport cage for a few minutes before entering Rat Park, their play area.
This became our Wait For It research program. We dubbed this new line of study UPERs — Unpredictable Positive Experience Responses — in which rats were trained to wait for events signaling rewards presented at unpredictable times. In contrast, control rats received their rewards immediately at a predictable time each day.
Preliminary results suggest that rats required to wait for their rewards show signs of shifting from a pessimistic cognitive style to an optimistic one in a test designed to measure rodent optimism. They also performed better on cognitive tasks and were bolder in problem-solving strategies. We linked this program to our lab’s broader interest in behaviorceuticals, a term I coined to suggest that experiences can alter brain chemistry similarly to pharmaceuticals.
The tale of the rat tail
It wasn’t just the effects of anticipation on rat behavior that caught our attention. One day, a student noticed something strange: One of the rats in the group trained to expect positive experiences had its tail straight up with a crook at the end, resembling the handle of an old-fashioned umbrella.
I had never seen this in my decades of working with rats. Reviewing the video footage, we found that the rats trained to anticipate positive experiences were more likely to hold their tails high than untrained rats. But what, exactly, did this mean?
Curious, I posted a picture of the behavior on social media. Fellow neuroscientists identified this as a gentler form of what’s called Straub tail, typically seen in rats given the opioid morphine. This S-shaped curl is also linked to dopamine. When dopamine is blocked, the Straub tail behavior subsides.
Natural forms of opiates and dopamine — key players in brain pathways that diminish pain and enhance reward — may be telltale ingredients of the elevated tails in our anticipation training program. Observing tail posture in rats adds a new layer to our understanding of rat emotional expression, reminding us that emotions are expressed through the entire body.
Although we can’t directly ask rats if they enjoy driving, we created a behavioral test to gauge their motivation to get behind the wheel. This time, instead of giving rats only the option of driving to the Froot Loop tree, they could also make a shorter journey on foot.
Surprisingly, two of the three rats chose to take the less efficient path of turning away from the reward and running to the car to drive to their Froot Loop destination. This response suggests that the rats enjoy both the journey and the rewarding destination.
Lessons on enjoying the journey
We’re not the only team investigating positive emotions in animals.
Neuroscientist Jaak Panksepp famously tickled rats, demonstrating animals’ capacity for joy.
Research has also shown that desirable low-stress rat environments retune their brains’ reward circuits. In the 1950s, neuroscientist Curt Richter demonstrated how the act of rescuing wild rats from a swim challenge could instill hope, prompting them to keep swimming far longer in anticipation of another rescue.
The driving rat project has opened new and unexpected doors in my behavioral neuroscience research lab. While it’s vital to study fear and stress, positive experiences also shape the brain in significant ways.
These rats offer insights into the neural principles guiding everyday behavior. Instead of pushing buttons for instant rewards, they remind us that planning, anticipating and savoring the journey may be essential for a healthy brain. I taught rats to drive, but they taught me to enjoy the ride.
Kelly Lambert is a professor of behavioral neuroscience at the University of Richmond. She is also the author of “The Lab Rat Chronicles: A Neuroscientist Reveals Life Lessons from the Planet’s Most Successful Mammals,” among other books.
“This article originally appeared in The Washington Post and was created in collaboration with The Conversation. It has been adapted with permission