In an experiment that initially seemed outlandish, we taught rats to drive tiny cars. While the project started as a fun way to study animal behavior, it led us to unexpected insights about how positive experiences – and the anticipation of them – shape not just our behavior, but also the brain’s ability to learn and adapt. What began as a simple experiment with a plastic cereal container became a window into understanding how anticipation and joy can influence animal behavior and brain chemistry.

The Birth of the Rat Car

We created our first rodent car out of a plastic cereal container. After some trial and error, we discovered that rats could learn to drive forward by pressing a small wire that acted like a gas pedal. This was just the beginning. Soon, the rats were steering with remarkable precision to reach a treat – a Froot Loop. This study offered an interesting glimpse into how animals can learn complex tasks, adapting their brains to new challenges in much the same way humans learn new skills.

Enriched Environments: A Boost for Brain Plasticity

As expected, rats that lived in enriched environments – spaces filled with toys, space, and social companions – learned to drive faster than those in standard cages. This reinforced the idea that a complex environment enhances neuroplasticity: the brain’s ability to adapt and change based on its surroundings. These findings added to the growing body of research suggesting that when animals (and humans) are stimulated and challenged, their brains grow more flexible, able to handle new tasks and experiences.

The Rise of the Rat-Operated Vehicle (ROV)

After our initial success, the project continued to evolve with the help of robotics professor John McManus and his students, who designed upgraded versions of the rat cars. These new ROVs – rat-operated vehicles – were equipped with rat-proof wiring, indestructible tires, and ergonomic levers, making them more akin to a rodent version of Tesla’s Cybertruck.

Despite their newfangled nature, I couldn’t help but smile at the irony. Laboratory rats, traditionally housed in environments with dirt, sticks, and rocks, were now driving around in cars! While rats may never encounter such cars in the wild, these vehicles provided an interesting and engaging way to study how animals acquire new skills.

The Motivation to Drive: A Lesson in Anticipation

One of the most fascinating aspects of the project was discovering how intensely motivated the rats were to drive. Often, the rats would jump into the car and begin revving the “lever engine” even before the car hit the road. Why were they so eager? What did this behavior mean?

Through operant conditioning, we taught the rats step-by-step to perform the actions necessary to drive. By using Froot Loops as a reward, the rats learned to associate their driving actions with a positive outcome, much like how we, as humans, learn new behaviors through rewards and repetition. But there was something more to it than just the reward – the rats were anticipating something pleasurable, and that anticipation itself seemed to fuel their motivation.

The Joy of Anticipation: Insights from the Pandemic

In the summer of 2020, during the emotional isolation of the Covid-19 pandemic, I noticed something unexpected. Three driving-trained rats, upon seeing their vehicle, eagerly ran to the side of their cage, jumping as if they were anticipating something fun – much like a dog would when asked if it wants to go for a walk. This behavior seemed to hint at something deeper: Could these rats be experiencing something akin to joy or excitement as they anticipated their drive?

This moment was pivotal in shifting the focus of our research. We began exploring the role of anticipation in shaping brain activity and behavior, recognizing that positive emotions – like joy and excitement – play an important role in mental and physical health, not just in humans, but in animals too.

The Wait For It Experiment: How Anticipation Shapes Behavior

In collaboration with postdoctoral fellow Kitty Hartvigsen, we designed a new experiment: the “Wait For It” protocol. This study focused on how waiting for rewards influences behavior. Rats were trained to anticipate a treat, like a Froot Loop, by waiting for a short period before receiving it. In contrast, control rats received their rewards immediately.

This research helped us explore how anticipation affects behavior in animals. The results were fascinating: rats that had to wait for their rewards showed more optimistic traits than those who received immediate rewards. These rats performed better in cognitive tasks and were more likely to take bold approaches to problem-solving. This shift from a pessimistic to an optimistic mindset was linked to changes in brain activity, particularly in regions associated with reward processing.

The Straub Tail: A Key to Understanding Anticipation

During one of our studies, we noticed something peculiar: one of the rats had a tail that was held high, with a crook at the end, resembling an old-fashioned umbrella. This behavior, known as the Straub tail, is typically associated with opioid use, but in our case, it appeared to be linked to the rats’ heightened anticipation of positive experiences.

By studying this behavior, we found that rats trained to anticipate rewards were more likely to exhibit this tail posture, suggesting that their brains were in a heightened state of reward anticipation. The Straub tail is linked to dopamine, a neurotransmitter involved in reward processing, and seeing this behavior helped us better understand how emotions and anticipation are physically expressed in rats.

The Journey Matters: Enjoying the Ride

In one particularly interesting experiment, we gave rats the option of taking a shorter journey on foot or a longer one by car to reach their Froot Loop reward. Surprisingly, many of the rats chose to drive, even though the car trip took longer. This suggested that, just like humans, rats enjoyed the journey – the act of driving – as much as the destination itself.

This finding was significant because it showed that the rats weren’t just motivated by the reward. They were also motivated by the act of driving and the anticipation of the enjoyable experience. This behavior reinforced the idea that positive experiences, and the anticipation of them, play a crucial role in motivating us and shaping our behavior.

Broader Implications: How Anticipation Shapes Our Lives

The research on rats has broader implications for understanding human behavior. Just as rats can be trained to anticipate rewards, humans, too, are driven by the anticipation of pleasurable experiences. The ability to look forward to something positive can help shape our behavior, drive persistence, and improve our overall mental health.

In a world where instant gratification is often the norm, the rats taught me a valuable lesson: it’s not always the immediate reward that matters. Sometimes, it’s the anticipation of a good experience that can lead to greater happiness, motivation, and success.

Conclusion: The Lessons of the Driving Rats

The Driving Rats project has opened new doors in behavioral neuroscience, showing us that anticipation and positive emotions play a significant role in shaping brain function and behavior. Just as we studied how chronic stress affects the brain, we’ve also explored how anticipation of positive experiences can help maintain brain health and motivation. In a world of instant gratification, the rats remind us that enjoying the journey – and learning to anticipate what’s to come – might just be the key to a healthy and happy brain.