A cognitive behaviour like regret was believed to be unique to humans until now. But scientists have confirmed rats show regret too and such finer emotions may not be uniquely and fundamentally human.
To measure regret, University of Minnesota’s professor of neuroscience A David Redish and Adam Steiner, a graduate student, started from the definitions of the word that economists and psychologists have identified in the past.
“Regret is the recognition that you made a mistake, that if you had done something else, you would have been better off,” said Redish. “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 and Steiner developed a new task in which rats decided how long they were willing to wait for certain foods. “It’s like waiting in line at a restaurant,” 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 show 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,” said Redish. “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.”
