Check out interesting rat experiments and research into rat behavior, health & more.
Rats Avoid Harming Other Rats (2020)
A study gave rats a choice between two levers that could deliver candy. Once rats showed a preference for one of the levers, the researchers wired it to deliver a mild but unpleasant shock to a neighboring rat. As soon as pulling their preferred lever harmed their neighbor, rats stopped using the lever to get a treat for themselves. Rats showed this altruism whether the neighboring rat was a cage mate or a stranger.
The study even showed that humans and rats have similar brain chemistry with an anterior cingulate cortex that regulates harm aversion. This region has neurons that map the witnessed or heard pain of another rat onto the witness’s pain neurons. When brain activity in this region was chemically reduced, the rats would not stop harming another rat for the treat.
Rat Empathy Study Shows Rats Are Driven by Empathy to Help Other Rats (2011)
Do rats have emotions? Yes, including the ability to empathize! This University of Chicago study found that rats demonstrate empathy for other rats and actively help them. Rats that can see and hear a trapped cage mate become agitated and actively free them from a restrainer tube. Even more, when given the choice between freeing their friend and eating a big stash of chocolate chips, rats were just as likely to free their friend instead of going right for the chocolate. At the very least, they tended to save some chocolate for their cage mate – a huge ask for a food-motivated rat with a chocolate chip horde!
Rats Remember and Reciprocate When Another Rat Is Kind (2015)
A 2015 study was the first time researchers found direct reciprocation in animals. The study found rats were most helpful or kind to rats that had helped them before. Rats don’t just remember which rats provide them help, they also remember the quality of help and adjust their behavior to invest more to help those rats in the future.
Rats Show Regret After Making a Wrong Decision (2014)
This hilarious rat experiment involved a setup the researchers called “restaurant row.” Rats ran around a circle past four spokes, each leading to a different “restaurant” that would give them a specific flavor of food. As the rat approached the entrance of the spoke, a tone would sound to indicate how long they would need to wait to receive the food. The rat could choose to stay or leave and try their luck at the next restaurant.
Rats had individual thresholds based on their preferences for the flavors. Waiting 20 seconds for a cherry-flavored treat might be a good deal to one rat but waiting the same amount of time for the chocolate flavor would be a bad deal.
When rats passed up a good deal and were confronted with a bad deal (the same or longer wait for a worse flavor or even a shorter wait for a flavor they don’t like), they demonstrated regret by looking back at the previous restaurant. One of the lead researchers said, “It looked like Homer Simpson going, ‘D’oh!'” They would also eat the food very quickly and rush to the next restaurant instead of taking their time to enjoy their food and groom like they would when they got a good deal.