Brain scans show how curiosity engages the brain’s circuits for memory and reward, increasing our ability to learn new information.

Have you ever found yourself reading the same boring sentence over and over again without remembering what it says? A new study published in Neuron may be able to explain why.

The research team found that curiosity boosts activity in and interaction between three parts of the brain: the nucleus accumbens (NAcc) and substantia nigra/ventral tegmental area (SN/VTA), which are parts of the brain’s reward circuit, and the hippocampus, which is responsible for the formation of new memories.

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To measure curiosity, the researchers took a group of volunteers and had them rate a series of trivia questions based on whether they knew the answer already and how curious they were to learn what the answer was. Then, the researchers measured their brain activity using functional magnetic resonance imaging (fMRI) while volunteers learned the answers to the questions.

For each item, the participants viewed the question, then were shown an unrelated, neutral face for two seconds before the answer was displayed. Afterwards, and again the following day, they took a test to see which answers they remembered, as well as which faces.

As expected, the volunteers were better at remembering the answers they were curious to know, remembering about 17 percent more correct answers to those questions. But they were also 4 percent better at recalling the faces shown after those questions — uninteresting, unrelated information. The memory differences lasted into the next day.

So how does curiosity help you learn something totally unrelated? The answer may lie in the way the brain anticipates and rewards learning.

Scientists have known for years that the active process of learning involves the hippocampus. “The surprising thing in our study is that activity in the hippocampus increased while someone is waiting for the interesting information, almost as if curiosity is warming up the hippocampus ahead of time,” said Matthias Gruber, lead study author and a postdoctoral researcher at the University of California, Davis, Center for Neuroscience, in an interview with Healthline. “Curiosity … may put the brain in a state that is more likely to retain new information, even if that information is not what got you curious in the first place.”

The hippocampus wasn’t the only brain region involved in curiosity — the NAcc and SN/VTA also showed greater activity when the person was curious. “This means that curiosity is recruiting key areas of the ‘reward circuit,’ suggesting that satisfying curiosity may feel rewarding because it stimulates a very basic neural circuit that responds to more … significant rewards,” Gruber said.

The hippocampus and the SN/VTA also increased their communication when anticipating an answer. The more they communicated, the better participants were at learning the new information.

“Some individuals learned a lot better when they were curious, and others less so,” Gruber explained. “People who showed more activity in these brain areas showed more enhanced learning for incidental material when they were generally curious. This suggests that the effects of curiosity on learning vary substantially from person to person, and those differences are intricately linked to brain areas that process reward and form memories.”

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Gruber hopes that his findings will be useful for educators. “Teachers often have to convey material that is not of general interest to students,” he said. “Instruction might be improved by first sparking students’ curiosity with questions that they are motivated to answer, and then presenting the less interesting material in that context.”

The research could also shed light on conditions that affect reward and memory, such as neurological conditions like Parkinson’s disease, traumatic brain injuries, depression, and aging. Curiosity could be used to help shore-up damaged reward circuits, or the reward circuit could be stimulated directly to give memory a boost.

Although a 4 percent increase doesn’t seem like a lot, Gruber thinks that the effects of curiosity may be much larger than he could measure in the lab.

“We are potentially underestimating the effects of curiosity in the real world,” he said. “Even if we were able to induce curiosity, the environment in the lab is still quite artificial and we might not be able to induce curiosity as strong as in the real world. We would expect that effects of curiosity in real life might be even bigger.”

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