Deal or No Deal?

From this site:

In one of those inspired bits of research we love so much, a team at Duke University trained a group of rhesus macaques to play a game based on Deal or No Deal.

The researchers gave the macaques a choice of eight white squares to pick up. Underneath each was a colour representing a prize, with green bringing the best reward - a sugary drink. After picking a square, the animals were shown the prizes they had passed up. ...

Brain scans revealed activity in the anterior cingulate cortex (ACC), a region known to monitor the consequences of actions when the monkeys won a prize. But the same area also lit up when they were shown what they had missed, indicating that they were thinking about what might have been.

"This is the first evidence that monkeys, like people, have 'would-have, could-have, should-have' thoughts," said Ben Hayden, a researcher at the Duke University Medical Center and lead author of the study.

Even the macaques got sucked into that troubling, stressful, "what if" thinking. Wow!