If you give a mouse a cookie, he'll ask for a glass of milk.
If you give a rat a tiny car, he'll drive it to his Froot Loops reward, new research suggests.
A study to be published in the peer-reviewed journal Behavioural Brain Research looked at how learning complex skills improved rats' emotional resilience, and the results could affect further research on the human brain, the study author says.
The experiment involved two groups of rats: one that lived in an "enriched environment" and another that lived in standard laboratory housing. The rats in the enriched environments were given multiple-level cages as well as objects including pieces of wood and plastic balls that changed weekly. The standard housing group lived in single level cages.
Once the rats were 5 months old, they were introduced to the rodent-operated vehicle, or ROV – the tiny cars they would soon learn to drive. The ROV featured a plastic container with an aluminum floor plate and copper bars in the windows.
When rats grabbed the bars, the ROV moved forward. When they let go, it stopped.
The rats were then trained to voluntarily enter their vehicles. A food reward, Froot Loops cereal, was placed at the end of their course. As the experiment went on, the cereal was placed further and further away, requiring the rats to learn more complex driving techniques.
"They learned to navigate the car in unique ways and engaged in steering patterns they had never used to eventually arrive at the reward," study author Kelly Lambert told magazine New Scientist.
The results showed that rats living in enriched environments "exhibited more robust driving performance" compared to those living in the standard cages, the study says.
To understand how driving affected the rats' brains, researchers turned to the animal feces.
The hormones corticosterone (CORT) and dehydroepiandrosterone (DHEA), which could indicate stress levels, were measured in the rats' feces to determine the animals' emotional responses to driving.
There was no difference in the ratio of CORT to DHEA between the two groups, but both groups showed levels that indicated a higher emotional resilience after driving.
"It is likely that driving gives the rats a sense of control over their environment," Lambert, a psychology professor at the University of Richmond, told CNN. "In humans, we would say that it enhances a sense of agency or self-efficacy."
Lambert says the study provides insights into how complex tasks can bolster an animal's emotional resilience. Completing tasks that reduce stress, like a rat driving a tiny car, can over time build an emotional response against mental health disorders, Lambert told CNN.
"There's no cure for schizophrenia or depression," she told the AFP. "And we need to catch up, and I think we need to look at different animal models and different types of tasks and really respect that behavior can change our neurochemistry."
However, studies that use mice, rats or other animals do not always translate when tested in humans. Animals are helpful for studying the safety of potential new treatments, but beyond that, don't count on them, Gregory Petsko, a neurological researcher at the Weill Cornell Medical School, told NPR in 2017.
Still, many studies are conducted on animals in addition to cells and humans.
"Research in humans is closest to application," stresses Meagan Phelan, Science Press Package executive director at the American Association for the Advancement of Science.
Contributing: Ashley May, USA TODAY; Follow USA TODAY's Ryan Miller on Twitter: @RyanW_Miller
This article originally appeared on USA TODAY: Rats can drive tiny cars, helping their emotional health, study says