Gambling monkeys forfeit prize to see if they won

Rhesus macaques were presented with a video gambling task in which they consistently chose to learn in advance if they picked the winning option—and were willing to give up 25 percent of their winnings to get the result right away. (Credit: Geoff Gallice/Flickr)

Monkeys are so curious they’re willing to give up a big part of a prize just to quickly know if they won anything at all.

“It’s like buying a lottery ticket that you can scratch off and find out if you win immediately, or you can buy one that has a drawing after the evening news,” says Benjamin Hayden, professor in brain and cognitive sciences at the University of Rochester and co-lead author of the study published in the journal Neuron.

“Regardless, you won’t get the money any more quickly, or in the case of the monkeys, they won’t get the squirt of water any sooner. They will just find out if they selected the winning option.”

In the study, rhesus macaques were presented with a video gambling task in which they consistently chose to learn in advance if they picked the winning option.

The monkeys didn’t receive their prize any sooner, which was a measure of juice or water; they were simply informed immediately if they selected a winner.

Paying for information

“When it’s simply a choice between getting the information earlier or not, the monkeys show a pretty strong preference for getting it earlier. But what we really wanted to do is quantify this preference,” says first author and lead researcher Tommy Blanchard, a PhD candidate in Hayden’s lab.

In the video gambling experiment, graduated colored columns illustrated the amount of water that could be won. The monkeys showed more curiosity when the stakes—or columns—were higher.

The monkeys not only consistently selected the gamble that informed them if they picked a winner right away, but they were also willing to select that option when the winnings were up to 25 percent less than the gamble that required them to wait for the results.

“One way to think about this is that this is the amount of water the monkeys were willing to pay for the information about if they made the correct choice,” Blanchard says.

“That 25 percent was really surprising to us—that’s pretty big,” Hayden says. “These monkeys really, really want that information, and they do these gambling tasks repeatedly and never get bored of them—it’s intrinsically motivated.”

Rewarding curiosity

The study helps to build a broader understanding for how curiosity, or information seeking, is processed and rewarded in the brain, the researchers say.

Like monkeys, when we’re curious we evaluate what we’d be willing to pay—or give up—to satisfy our curiosity. In the case of gambling, we also factor in the potential of winning a prize.

So when we make a choice, it depends on the sum of those two things: the gamble (the money we might win) and the value of finding out. And those two things need to be combined in order to make decisions about that gamble.


Earlier work suggests that these components are combined in the brain’s dopamine system. The new study goes back a step to a region of the brain called the orbitofrontal cortex (OFC).

“I think of the OFC as the workshop of economic value, where, in this case, you have the value of the gamble and the value of the information—the raw materials—but they haven’t yet been combined,” Hayden says.

“This study seems to have revealed that the mixing of the raw materials happens somewhere between the OFC and the dopamine system. We now have two points in the circuit.”

“One of the reasons this research is important,” Hayden says, “is because this basic desire for information turns out to be something that’s really corrupted in people with anxiety, depression, obsessive-compulsive disorder, and addiction, for example.”

“We think that by understanding these basic circuits in monkeys we may gain insights that 10 to 15 years down the road may lead to new treatments for these psychiatric diseases.”

Ethan S. Bromberg-Martin of Columbia University is a co-senior author of the study.

The National Institutes of Health supported the research.

Source: University of Rochester