Much like humans, monkeys too exhibit signs of regret, and they wonder themselves what might have been, according to a recent study published by researchers from Yale.

The study, published in the Neuron journal, suggests that aside from regrets, monkeys often wonder about how different actions would lead to different outcomes; as researchers state, aside from being extremely interesting in itself, this could also shed some light on some of the most basic human psychological traits.

The general belief is that animals learn only on their previous experiences, mostly on a trial and error basis. But Daeyeol Lee, a professor of neurobiology at the Yale School of Medicine said he has long believed that this was inaccurate, and set out to prove his hunch; he succeeded.

“When people have regret, they’re thinking about what could have happened; it’s about imagining what could have happened,” said Lee, co-author of the study. “The reason you do this is because it actually broadens the potential for learning tremendously. It seems like such a fundamental question that I would be surprised if it were exclusive to humans.”

To test their theory, researchers set out and taught the monkeys to play a computer simulation of ‘rock, paper, scissors’, while monitoring their brain’s activity. If they won, they would get a large reward, if they tied, a small reward, and they got nothing when they lost. Most of the monkeys, they observed, would pick whichever symbol they would have won with in the previous game. In other words, Lee said, they were able to think abstractly and imagine an alternative outcome.

With the help of brain imaging material, the Yale researchers were able to pinpoint the activity in the brain triggered by this kind of thinking, and the different forms that it takes. According to them, regret takes place in two different forms, both of which take place in parts of the prefrontal cortex. Most regret is also good, and helps you learn and evolve.

“Your brain is running this mental simulation about how you could do things differently in the future to get a better outcome.”

But when people obsess about their regrets, this often leads to depression.

“It’s an important first step,” he said. “If someone has a pathological amount of regret, and you want to ameliorate it some way, you can target those areas. And when you’re testing those drugs, then you know where to look.”