It’s easy to assume that the most surprising aspect of a research project where scientists teach rats to drive would be the mere achievement of getting the rodents behind the wheel.
But the researchers now say their rodent students have in turn taught them a “profound” and unexpected lesson of their own. They’ve discovered that the rats seem to genuinely enjoy – and eagerly anticipate – getting behind the wheel.
Researchers in Virginia first made global headlines in 2019 when they succeeded in training rats to drive small cars made out of plastic cereal containers, powered by grasping a small wire acting like an acceleration pedal, in exchange for Froot Loops cereal.
“Before long, they were steering with surprising precision to reach a Froot Loop treat,” said Kelly Lambert, a professor of behavioural neuroscience at University of Richmond, noting that rats housed in environments with friends, toys and space learned more quickly than those in sparser surroundings.
Those efforts have since continued, with Professor Lambert describing new vehicles “akin to a rodent version of Tesla’s Cybertruck” equipped with rat-proof wiring, “indestructible tyres and ergonomic driving levers”.
Sharing details of their ongoing research into how rodents acquire new skills, Prof Lambert wrote in The Conversation: “Unexpectedly, we found that the rats had an intense motivation for their driving training, often jumping into the car and revving the ‘lever engine’ before their vehicle hit the road.”
“The rats also taught me something profound one morning during the pandemic,” wrote Prof Lambert, adding: “When I walked into the lab, I noticed something unusual: The three driving-trained rats eagerly ran to the side of the cage, jumping up like my dog does when asked if he wants to take a walk.
“Had the rats always done this and I just hadn’t noticed? Were they just eager for a Froot Loop, or anticipating the drive itself? Whatever the case, they appeared to be feeling something positive – perhaps excitement and anticipation.”
Curious to discover whether she was witnessing “something akin to joy in a rat”, Prof Lambert and her team shifted their focus to explore how positive events – and the anticipation of them – can shape our brain’s neural functions.
In a research programme called Wait For It, Prof Lambert and postdoctoral researcher Kitty Hartvigsen designed a new protocol to ramp up levels of anticipation and train the rats to wait for rewards.
In this research, rats were forced to wait 15 minutes after a Lego block was placed in their cage before receiving a Froot Loop, to wait before entering their play area, and to complete challenges such as shelling sunflower seeds prior to eating.
Preliminary results of brain monitoring suggest rats forced to wait for rewards “show signs of shifting from a pessimistic cognitive style to an optimistic one”, and “performed better on cognitive tasks and were bolder in their problem-solving strategies” compared to a control group of rats who received their rewards instantly, according to Prof Lambert.
And there appeared to be outwardly visible signs of benefits among the rats forced to wait for a reward.
“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,” said Prof Lambert.
The researchers found that rats trained to anticipate positive experiences were more likely to hold their tails high than untrained rats – in a phenomenon known as “Straub tail”, which is typically seen in rats given morphine, and linked to the “feel-good” hormone dopamine.
In a further test to assess why the rats were motivated to drive, the rodents were given the option of driving to the Froot Loop in their vehicles – or instead making a shorter journey by 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,” Prof Lambert wrote. “This response suggests that the rats enjoy both the journey and the rewarding destination.
She added: “As animals – human or otherwise – navigate the unpredictability of life, anticipating positive experiences helps drive a persistence to keep searching for life’s rewards. In a world of immediate gratification, these rats offer insights into the neural principles guiding everyday behaviour.
“Rather than pushing buttons for instant rewards, they remind us that planning, anticipating and enjoying the ride may be key to a healthy brain. That’s a lesson my lab rats have taught me well.”
