The Itch of Curiosity

Curiosity is one of those personality traits that gets short scientific shrift.

It strikes me as a really important mental habit – how many successful people are utterly incurious? but it’s also extremely imprecise. What does it mean to be interested in seemingly irrelevant ideas? And how can we measure that interest?

While we’ve analyzed raw intelligence to death – scientists are even beginning to unravel the anatomy of IQ – our curiosity about the world remains mostly a mystery. (According to one review of the literature, the amount of research on curiosity peaked in the late 1940s.)

Einstein would not be pleased: “I have no special talents,” he once declared. “I am only passionately curious.”

Nevertheless, progress is occurring; our curiosity about the brain is even leading us to understand curiosity.

One of the most interesting recent papers comes from the lab of Colin Camerer at Caltech, and was led by Min Jeong Kang. The experiment itself was straightforward: Nineteen Caltech undergrads were asked 40 trivia questions while in a brain scanner. After reading each question, the subjects were told to silently guess the answer, and to indicate their curiosity about the correct answer.

Then, they saw the question presented again, followed by the correct answer. That’s it.

The results of the fMRI experiment are an intriguing, if limited, glance at the neural processes underlying creativity. The first thing the scientists found is that curiosity obeys an inverted U-shaped curve, so that we’re most curious when we know a little about a subject (our curiosity has been piqued) but not too much (we’re still uncertain about the answer).

This supports the information gap theory of curiosity, which was first developed by George Loewenstein of Carnegie-Mellon in the early 90s. According to Loewenstein, curiosity is rather simple: It comes when we feel a gap “between what we know and what we want to know”.

This gap has emotional consequences: it feels like a mental itch, a mosquito bite on the brain. We seek out new knowledge because we that’s how we scratch the itch.

The fMRI data nicely extended this information gap model of curiosity. It turns out that, in the moments after the question was first asked, subjects showed a substantial increase in brain activity in three separate areas: the left caudate, the prefrontal cortex and the parahippocampal gyri.

The most interesting finding is the activation of the caudate, which seems to sit at the intersection of new knowledge and positive emotions. (For instance, the caudate has been shown to be activated by various kinds of learning that involve feedback, while it’s also been closely linked to various parts of the dopamine reward pathway).

The lesson is that our desire for abstract information – this is the cause of curiosity – begins as a dopaminergic craving, rooted in the same primal pathway that also responds to sex, drugs and rock and roll.

This reminds me of something Read Montague, a neuroscientist at Baylor College of Medicine, told me a few years ago: “The guy who’s on hunger strike for some political cause is still relying on his midbrain dopamine neurons, just like a monkey getting a sweet treat,” he said. “His brain simply values the cause more than it values dinner…You don’t have to dig very far before it all comes back to your loins.”

The elegance of this system is that it bootstraps a seemingly unique human talent to an ancient mental process. Because curiosity is ultimately an emotion, an inexplicable itch telling us to keep on looking for the answer, it can take advantage of all the evolutionary engineering that went into our dopaminergic midbrain. (Natural selection had already invented an effective motivational system).

When Einstein was curious about the bending of space-time, he wasn’t relying on some newfangled circuitry. Instead, he was using the same basic neural system as a rat in a maze, looking for a pellet of food. I’ll let the scientists have the last word:

Understanding the neural basis of curiosity has important substantive implications. Note that while information-seeking is generally evolutionarily adaptive, modern technologies magnify the amount of information available, and hence the potential effects of curiosity.

Understanding curiosity is also important for selecting and motivating knowledge workers who gather information (such as scientists, detectives, and journalists).

The production of engaging news, advertising and entertainment is also, to some extent, an attempt to create curiosity. The fact that curiosity increases with uncertainty (up to a point), suggests that a small amount of knowledge can pique curiosity and prime the hunger for knowledge, much as an olfactory or visual stimulus can prime a hunger for food, which might suggest ways for educators to ignite the wick in the candle of learning.

Image Courtesy: Wikipedia