When a mouse faces two doors, it turns out the mouse will pick the one that tells the future—even if it means getting less water. Scientists at Columbia University discovered that mice have a strong desire for knowledge, just like humans.
Researchers at Columbia's Zuckerman Institute wanted to understand where curiosity comes from in the brain. Jennifer Bussell, Ph.D., an associate research scientist at Columbia, led the study published in Nature Neuroscience. She designed a simple game for the mice: two holes to choose from. One hole puffed out a smell (like cut grass) that told the mouse whether water was coming. The other hole gave no clues at all. Both holes offered the same chance of getting water.
The results surprised the researchers. The vast majority of mice picked the hole that predicted the future. Even when the scientists changed the rules so that the information hole gave less water, the mice still chose it. "These animals had such a strong desire for knowledge about upcoming events that they would pay to receive it," Bussell said.
To understand what was happening in the brain, Bussell watched thousands of neurons as the mice played the game. She focused on a brain region called the orbitofrontal cortex, which helps animals make decisions. About 20 percent of neurons in this area behaved differently when the mice expected information. These cells seemed to signal how valuable the knowledge was to each mouse.
This finding adds to what we know about curiosity. Philosophers have thought about it for thousands of years—in fact, Aristotle wrote that humans "by nature desire to know." Modern scientists have shown that rats and pigeons also seek out information. Bussell's work takes this further by showing exactly which brain cells respond to the value of knowledge itself.
The research might eventually help explain why humans feel so driven to learn, even when learning offers no immediate reward. "One of the great joys of life is getting to be curious about everything around us," Bussell said. She noted the question touches on how children learn, how scientists make discoveries, and how we all navigate a world full of information—and misinformation.
Bussell worked with Ethan Bromberg-Martin, Ph.D., from Johns Hopkins University School of Medicine, who previously showed that parts of the brain treat information like food or other tangible rewards. The new study builds on that work by identifying the specific brain signals that compute the value of knowledge. Next, scientists hope to learn exactly how these neural signals form in the first place.