Regrets? Even gameshow-playing monkeys have a few…
A monkey version of the TV gameshow “Deal or No Deal” has demonstrated that the animals are capable of experiencing regret – the first time a non-human species has been shown capable of doing so.
In experiments led by Ben Hayden of the Duke University Medical Center in North Carolina, a group of rhesus macaques were asked to choose from a series of identical white cards.
When turned over, the cards revealed a colour with each colour corresponding to a different amount of juice.
Over weeks the monkeys were trained to associate the colour green with as much juice as they could drink and other colours with low value rewards.
They also learnt to recognize a pattern whereby the cards were shuffled clockwise between each game.
By scanning the monkeys’ brains as they made their choices, the researchers discovered that the experiment lit up a part of the brain known as the anterior cingulated cortex which is usually associated with monitoring the consequences of actions and mediating resulting changes in behaviour – with more neurons lighting up when the card turned over was green.
But the same neurons also lit up when they choose the wrong card, suggesting they were thinking about what might have been.
When the monkeys failed to choose the top reward, their brain activity also suggested they tried harder to pick the right card the next time.
“This is the first evidence that monkeys, like people, have ‘would-have, could-have, should-have’ thoughts,” said Hayden.
Hayden said the research was the first suggesting that species other than humans were capable of thinking about not only what had happened but what could have happened.
“Reasoning about abstract things is fundamental to forming a philosophical perspective so it is important to know whether this is something that distinguishes humans or is shared with other animals,” he said.
Rhesus macaques are considered particularly smart by primate standards — with some scoring as well as students in their early 20s in maths tests.