Scientists used to think only humans feel regret, but some animals may also regret bad choices.

"Regret is the recognition that you made a mistake, that if you had done something else, you would have been better off," said study author David Redish, Ph.D., a professor of neuroscience in the University of Minnesota Department of Neuroscience.

Researchers at the University of Minnesota Academic Health Center created an experiment called "restaurant row" -- four different food stops a rat could make. At each entrance, a tone indicated how long the rat would have to wait to receive food. A rat could either stay, or choose to try something else. "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." Redish said.

The rats had preferences for specific foods and would only wait a certain amount of time to get it. The researchers decided to see what would happen if the rats skipped a 'good deal' only to discover a 'bad deal' at the next place. To the researchers' surprise, when the rats made a bad choice they stopped and looked back. This, they surmised, suggested they regretted their decision.

The researchers then used imaging to study the brain activity of the rats and found that when a rat made a mistake, the orbitofrontal cortex of the brain–the part of the brain believed to process regret in humans–was activated.

Although rats' regret response was similar to humans', the UofM researchers said they were unsure whether rats have human-like reflection about decisions. But they said the study shows that animal models may be used to better understand certain human behaviors.