Rats Can Feel Regret

Humans are not the only creatures that can feel regret. According to a new study, in certain situations, rats, too, can regret past decisions, National Geographic reports. 

Researchers monitored, via electrodes, the brain activity of four rats and focused on two key areas involved in decision-making. They then allowed the rats to spend one hour playing a somewhat complicated maze. NatGeo:

The maze consisted of a circle with four spokes radiating out from its circumference. At the end of three spokes was food flavored with banana, cherry, or chocolate. At the end of the fourth spoke was unflavored food. When a rat arrived at a spoke, a tone would sound before it received the food. The tone's pitch indicated how long the rat would have to wait before getting the treat; it could be anywhere from one to 45 seconds.

At that point, the animal could chose to stick around, or it could rush off to the next treat, in the hopes of the next one being available sooner. 

When rats made a bad choice—they left one piece of food, only to run down a hall that ended in another long wait—they showed visible signs of regret, the researchers told NatGeo. They looked over their shoulder, longingly gazing back at their would-be prize.

The team could also monitor which food flavor the rat was thinking about depending on which nerve-cell pathways activated in its brain. As NatGeo explains, the rats that regretted their decision would think about that specific flavor of food that they passed up: "'That's the regret,' says [neuroscientist David] Redish. Not only were the rats physically looking backward; they were also thinking about the choice they hadn't made."

In a way, these results are not too surprising, given that rats are one of the most intelligent animals around, possessing impressive (if frequently overlooked) "cognitive prowess," as one researcher wrote back in 1996. But actually being able to provide neurological evidence of that cognitive prowess in the form of human-like emotion is something exceptional, NatGeo adds. 

Rachel Nuwer | | READ MORE

Rachel Nuwer is a freelance science writer based in Brooklyn.