We’ve all have regrets. Now, a surprising new study from the University of Minnesota shows that humans aren’t the only ones to feel this way. Rats do, too.

David Redish, professor of neuroscience at the university and lead author of the study, has long been fascinated with decisionmaking. Specifically, why people make choices they are likely to regret.

So, for the past 14 years, Redish has researched the process that result in decisions — even bad ones.

“In a lot of cases, what you see is people making those decisions and regretting it the next day,” Redish said.

When Redish began his research, he never thought he would claim that rats can show regret, a cognitive behavior thought to be unique only to humans.

(Regret is defined as recognizing a mistake has been made, “whereas disappointment is the recognition that the world is not as good as you had hoped,” he explained.)

In an attempt to study decisionmaking in common lab rats, Redish and Adam Steiner, a neuroscience graduate student, strapped sensors on rats to track how they responded to different choices of food rewards. In the course of their research, Steiner noticed that when a rodent made a choice it didn’t like, it stopped and looked backward, as if feeling some kind of remorse.

After observing that behavior in a number of rats, Redish and Steiner created an experiment, called Restaurant Row, designed to induce regret. Rats in the lab had to choose whether to wait for a food they liked, or move onto another food station, which may or may not have a favorite food.

The rats that did move on and found the next option less appealing showed regretful behavior — stopping and looking back.

The research led to the discovery that rat brains are very much like human brains when it comes to regretting a poor choice. In fact, humans and rats both show regret for a missed opportunity in the same area (the orbitofrontal cortex) of their brains.

Redish said his animal-model research is being translated to help comprehend how regret affects human decisionmaking when that process is broken, such as in addictions.

“There are questions we can now ask that we didn’t know were questions,” Redish said.

Redish called his discovery “groundbreaking,” saying that it will help him expand his research.

“I live for days when somebody comes into my office and says ‘Hey, have you seen what my rats are doing? Looks like they are showing regret,’ ” Redish said. “That’s a great day.”