As any keen motorist will know, there is nothing like the freedom of driving along an open highway as the air rushes through your whiskers, filling you with joy down to the very tip of your tail.
Rats can not only be taught to drive, but they also “enjoy the ride” and will even take the long way round to drive to a treat because they derive pleasure from it, scientists have found.
Researchers from Virginia in the US found in 2019 that rats could be trained to drive a car made out of a plastic cereal container by grasping at a wire that propelled the vehicle forward.
Rats were observed taking a longer route to reach a treat if it meant they could drive rather than walk
“Before long, they were steering with surprising precision to reach a Froot Loop [breakfast cereal] treat,” wrote Kelly Lambert, a professor of behavioural neuroscience at the University of Richmond, on The Conversation website.
They found that rats housed in stimulating environments full of toys and companions picked up driving faster than others, showing that their brains benefited from the extra stimulation, making it easier for them to learn.
The original study was then beefed up. Researchers developed “new, improved rat-operated vehicles featuring rat-proof wiring, indestructible tires and ergonomic driving levers” to further their studies.
“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,” Lambert said.
On entering the laboratory for driving tests, Lambert noticed that “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”.
Rats in a stimulating environment with companions picked up driving more quickly than others
She mused: “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.”
They sought to test the impact of anticipation, to see if the rats really were looking forward to driving. She has been looking at the changes that take place in a rat’s brain when they are made to wait for their reward, rather than being given it immediately.
“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,” Lambert wrote, noting that this was linked with the release of dopamine, the hormone associated with motivation and reward.
The key test was to offer the rats a choice. They could either access the Froot Loop treat by making a short journey on foot or they could climb into the car and drive it the long way round to access the treat, delaying their reward.
“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,” Lambert wrote. “This response suggests that the rats enjoy both the journey and the rewarding destination.”
She noted that “anticipating positive experiences helps drive a persistence to keep searching for life’s rewards” and said that “planning, anticipating and enjoying the ride may be key to a healthy brain”.