Like Humans, Monkeys Know the Limits of Their Own Memory

Photo: Alfonso Paz Photo

Subtly different from plain old ignorance is something called meta-ignorance — it’s not just not knowing things, but a lack of awareness of what you don’t know.

If meta-ignorance had an opposite, it might be what scientists call metamemory: knowing where you have gaps in your knowledge and, just as importantly, understanding which memories you’re confident about and which ones are shakier. And according to a study published earlier this week in the journal Science, we aren’t the only ones that have it — monkeys, too, understand the limits of their own memory. From Smithsonian:

University of Tokyo physiologist Kentaro Miyamoto and collaborators showed two adult macaque monkeys a series of images. Then, they asked the monkeys to answer “yes” or “no” about whether they had seen these images before, using a joystick and a screen. After they chose their answer, the monkeys were then asked to “bet” on how confident they were in their answer. Monkeys that bet high on their memory and were correct received a large reward of juice, while the monkeys that bet low and were either correct or incorrect received a small reward of juice. Monkeys that bet high and ended up being incorrect received no reward and were forced to wait extra time before playing again.

For the second part of the study, the researchers attempted to pinpoint exactly where metamemory lived in the monkeys’ brains. Miyamoto and his colleagues observed the animals as they played the game within an MRI machine, making note of which regions showed the most activity as they placed their bets. Then, to make doubly sure they had the right info, the researchers gave the monkeys a drug that temporarily shut down the brain areas in question — and sure enough, the monkeys got a lot worse at betting.

As Smithsonian explained, knowing which parts of the brain are linked to metamemory will help scientists to further understand a complex phenomenon — one that’s a valuable asset when it comes to managing their social lives. “A monkey that can distinguish between when their memories are accurate and when their memories are inaccurate is going to be much better at getting along with the other monkeys in the troop,” Nate Kornell, a psychologist unaffiliated with the study, told the magazine. And, for that matter, knowing which of those monkeys to ditch.

Like Humans, Monkeys Know the Limits of Their Own Memory