You are not alone. Rats feel regret too, study says

There was the trip to Vegas where you met Judy. She said she was judge, but was unaccountably wearing a tutu and brandishing a more immediate form of justice that had nine tails.

There were the four years studying botany, the two spent with Brittany and the accidental, but not really, insider trading that got you six months.

Regrets, we all have a few. Yet we believe that, though other animals might have feelings, some are unique to our own intelligent systems.

Now researchers at the University of Minnesota are suggesting you're not so special. In a study loftily titled "Behavioral and neurophysiological correlates of regret in rat decision-making on a neuroeconomic task," they attempted to see whether rats could feel regret as we do.

They took great pains to differentiate regret from disappointment. To them, regret "entails recognition that an alternative (counterfactual) action would have produced a more valued outcome."

Yes, it's the knowledge -- and the concomitant pain in your entrails -- that you should have done something else.

Human beings show their regret within their orbitofrontal cortex. Could rats do something similar?

The researchers decided, quite naturally, to use food as the bait. They set up their experiments by making the rats wait for a certain amount of time to get food. The food was of differing quality. Would the rats wait for the good stuff? Or would they move on to a shorter line, only to regret making their decision?

What they found was that if the rats got fed up of waiting and moved onto another food option, they would look back wistfully, as you might toward the memory of one night spent with Crazy Henry.

The university's professor David Redish told BBC Nature News: "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."

The researchers said that once the rats made a bad decision and ended up eating less satisfying food, they changed their decision-making process. At the next food stop, they'd wait a little longer in the hope that this one would be more nourishing.

Professor Redish believes that the rats' reactions didn't express their need for the actual food itself.

He told BBC Nature News: "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."

There's a certain relief, if not even joy, to think that other species might be as good at beating themselves up as we are.

We look at rats and muse that they're slightly despicable little creatures, scavenging mercilessly and scurrying away at the first sign of threat.

They irritate, disturb, thieve, and occasionally kill people in movies. They behave more as opportunistic survivors than anything else.

So should we be completely surprised that they might have inner feelings just like ours?