We all make poor choices sometimes. Apparently, so do rats -- and, like most humans, they feel remorseful when they make an unfortunate decision. According to a new study published in the research journal Nature Neuroscience, rats appear to be the only other mammals to display signs of regret after choosing badly, undermining a long-held belief that humans are the only ones who would take it all back if we could.
"Regret is the recognition that you made a mistake, that if you had done something else, you would have been better off," David Redish, one of the members of the research team, told the BBC. "The hard part was that we had to separate disappointment, which is just when things aren't as good as you hoped. The key was letting the rats choose."
Redish and his team created an experiment involving multiple different food options for the rats in a line called "Restaurant Row." The premise was simple: the rats would wait around before being presented with different food options at different stops along the way; some stops presented food to the rats faster than others. The scientists measured how long the rats waited before becoming impatient.
The researchers found that when rats decided to give up on one stop and go on to the next, only to find themselves presented with a less tasty option, they would turn around and look back at the treat that could've been. But the rats didn't just look back wistfully; they also changed their future decisions, holding out for better treats instead of jumping ahead impatiently. According to Redish, these behaviors are all hallmarks of regret.
"In humans, a part of the brain called the orbitofrontal cortex is active during regret. We found that in rats recognizing that they made a mistake, their orbitofrontal cortex represented the missed opportunity," Prof Redish said. "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."