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February 14, 2015

Monkeys pass up rewards in favor of knowledge

Chuck Bednar for redOrbit.com - Your Universe Online

Monkeys are so eager to know things that they are willing to pass up the promise of a large reward in order to learn things more quickly, experts from the University of Rochester and Columbia University reported earlier this month in the journal Neuron.

The researchers presented rhesus macaques with a video gambling task in which they routinely sacrificed a significantly increased amount of winnings in order to discover right away whether or not they had won. In fact, they selected that option even when the winnings associated with it were up to 25 percent less than one which forced them to wait to learn of the outcome.

“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,” Benjamin Hayden, co-senior author of the study and a professor in brain and cognitive sciences at the University of Rochester, said in a statement. “Regardless, you won't get the money any more quickly.”

In the case of the monkeys, the reward was a squirt of juice or water, and when presented with a choice between getting information sooner rather than later, they showed a “strong preference” for learning the outcome as quickly as possible, added first author and Ph. D. candidate Tommy Blanchard. However, he and his colleagues set out to quantify that apparent preference.

“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,” said Blanchard. Hayden added that he and his co-authors were surprised that the macaques were willing to sacrifice so much in order to obtain that knowledge as soon as possible.

Humans and gambling for knowledge

The researchers explain that their study helps provide new insight into how curiosity is processed and rewarded within the brain. Like monkeys, humans tend to evaluate how much they will sacrifice in order to satisfy their curiosity, and when it comes to gambling, the size of a potential prize has to be factored into the decision. Thus, choices depend on a combination of two factors: the gamble involved (the size of the prize) and the importance and value of finding out.

Both of those factors need to be evaluated when it comes to making decisions about the gamble, the researchers said. Previous research suggests that the components are combined in the brain’s dopamine system, but the new study reviews at the step before that part of the process. It looks at what happens in a region of the brain known as 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 said. “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, 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,” he added. “We think that by understanding these basic circuits in monkeys we may gain insights that 10 to15 years down the road may lead to new treatments for these psychiatric diseases.”

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