Humans like to think we are special, that emotions are unique to us. However, recent research on animals continues to show that this just isn’t the case. As further proof, a University of Minnesota research team sought to determine whether rats were capable of feeling regret.

To do this, A. David Redish, Ph.D., a professor of neuroscience in the University of Minnesota Department of Neuroscience, and Adam Steiner, a graduate student in the Graduate Program in Neuroscience created, “Restaurant Row”.

In Restaurant Row, the rats were given a certain amount of time to select the foods they liked. Simultaneously, some foods, especially foods they particularly liked, took longer to acquire than others.

“It’s like waiting in line at a restaurant. If the line is too long at the Chinese food restaurant, then you give up and go to the Indian food restaurant across the street,” said Redish in a statement.

Because the researchers knew the individual preferences of the rats, they had the potential to  create good and bad deals in terms of the time cost of food.

Then, using definitions of regret established by psychologists and economists, Redish and Steiner then looked at the rats’ responses after the fact.

“Regret is the recognition that you made a mistake, that if you had done something else, you would have been better off. The difficult part of this study was separating regret from disappointment, which is when things aren’t as good as you would have hoped. The key to distinguishing between the two was letting the rats choose what to do,” said Redish.

At times the rats skipped a good deal and wound up with a bad deal. When this happened, the rats showed the same signs of regret that scientists expect to see in humans.

“In humans, a part of the brain called the orbitofrontal cortex is active during regret. We found in rats that recognized they had made a mistake, indicators in the orbitofrontal cortex represented the missed opportunity. Interestingly, the rat’s orbitofrontal cortex represented what the rat should have done, not the missed reward. This makes sense because you don’t regret the thing you didn’t get, you regret the thing you didn’t do,” said Redish.

The researchers hope that their work, published in Nature Neuroscience, will allow neuroscientists to better understand human behavior by building on the animal model of regret.

It is not clear from the study if rats are capable of guilt, but it remains a possibility. Guilt is different from simple regret. Guilt also requires empathy and the feeling of having been wronged; concurrently,  a University of Chicago study released in 2014 showed rats, like humans, were capable of empathy and pro-social behavior.