Washington: Scientists have found that rats show regret, a cognitive behaviour once thought to be uniquely and fundamentally human.
Researchers from the Department of Neuroscience at the University of Minnesota first studied the definitions of regret that economists and psychologists have identified in the past to measure the cognitive behaviour of regret.
"Regret is the recognition that you made a mistake, that if you had done something else, you would have been better off," said A David Redish, a professor of neuroscience in the University of Minnesota Department of Neuroscience.
"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," Redish said.
Redish and Adam Steiner, a student in the Graduate Programme in Neuroscience, who led the study, developed a new task that asked rats how long they were willing to wait for
"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 this task, which they named "Restaurant Row," the rat is presented with a series of food options but has limited time at each "restaurant."
Research findings showed rats were willing to wait longer for certain flavours, implying they had individual preferences.
Because they could measure the rats' individual preferences, Steiner and Redish could measure good deals and bad deals. Sometimes, the rats skipped a good deal and found themselves facing a bad deal.
"In humans, a part of the brain called the orbitofrontal cortex is active during regret. We found in rats that recognised they had made a mistake, indicators in the
orbitofrontal cortex represented the missed opportunity," said Redish.
"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," Redish added.
The findings were published in journal Nature Neuroscience.