Last week's announcement of the results of the BICEP2 experiment was an unusual candidate for a headline-grabbing science story. Sure, it had plenty of drama: a prediction made by an equation-wielding young physicist three decades before is finally confirmed at a remote South Pole observatory. The result reveals the "Big Bang's smoking gun" and "let's us see to the beginning of time." But this result, the "detection of B-mode polarization at degree angular scales,"will almost certainly never have any practical impact on our lives. Unlike a cure for cancer, a solution to global warming, or a method to build better batteries, the BICEP2 experiment mainly satisfies our curiosity. And yet curiosity is clearly a powerful motivator. Why are we so curious?
Curiosity isn't limited to humans. Richard Byrne, who studies animal cognition at the University of St. Andrews in Scotland, argues that many animals—from rats to monkeys to elephants—are curious: "they explore objects they haven’t seen before, they play around with all sorts of apparently ‘useless’ things." Curiosity is particularly valuable to species that are generalists, able to colonize many different habitats. These animals "need to respond rapidly to changing environments, so it pays to explore the world and build up a mental model of what is where and how to get there."
Research into the neural basis of curiosity is just beginning, but it's clear that our drive to explore unanswered questions is one of a set of important traits that we use to fill what some researchers call the cognitive niche.
Humans, though, take curiosity to an extreme. Our species' unusually long period of childhood is specifically devoted to exploration and learning, activities that are integral to proper brain development. In other words, curiosity is an important part of the biology of our brains. University of California-Berkeley psychologist Alison Gopnik and her colleagues argue that the emergence of an extended childhood in our evolutionary history, where others take care of our immediate survival needs, created a "context for the application of more powerful learning mechanisms." Among these learning mechanisms are a "newly sophisticated and general ability and motivation to learn about causation" and create powerful mental models of our social and physical environments.
To build these powerful mental models, Gopnik says, we have to make a trade-off between a goal-directed, practical learning to obtain actionable information about our world and a curiosity-driven exploration of the world. "Extended immaturity helps resolve that trade-off—a protected period of exploration as children allows us to exploit as adults." By balancing goal-directed learning and exploration, humans learn to extend their reasoning about cause-and-effect to situations they've never encountered before.
Curiosity is a strong driver of exploration. Neuroscientists are discovering that we feel curiosity so intensely because it acts through brain regions that come into play when we experience other strong feelings—regions associated with conflict, arousal, and reward. A group of researchers at Leiden University in the Netherlands tested the idea that "curiosity evoked by ambiguous, complex, or conflicting stimuli is an aversive condition associated with increased levels of arousal," and that relief of this arousal "is rewarding and promotes learning." The researchers studied volunteers' brain responses by piquing their curiosity with a blurry picture, and then either satisfied that curiosity by showing them a clear version of the same picture, or left the subjects hanging with a clear but obviously different picture. Their results were consistent with their theory: blurred pictures activated brain regions associated with "aversive emotional experiences," while showing the correct clear picture afterward activated brain regions associated with "reward processing." Another study, conducted by researchers at Caltech, using questions instead of pictures to stimulate their subjects' curiosity, found that curiosity increased activity in areas of the brain associated with memory. They suggested that curiosity about unexpected new information improves our memory of that information.
Research into the neural basis of curiosity is just beginning, but it's clear that our drive to explore unanswered questions is one of a set of important traits that we use to fill what some researchers call the cognitive niche. As a species we have traits that, as Harvard psychologist Steven Pinker puts it, "deploy information and inference, rather than particular features of physics and chemistry, to extract resources from other organisms in opposition to their adaptations to protect those resources." With sophisticated mental models of the world, and by using language, metaphor, and an innate capacity to make abstractions and extrapolations, we reason out our survival strategy. These abilities also open up the boundaries of our curiosity, let us turn our inquiries inward, and make it possible to pursue questions about the origins of ourselves and the universe.
So perhaps our excitement over last week's news about an esoteric confirmation of a very abstract theory with no practical application shouldn't be too puzzling. As a society, we pay people to understand what happened 10-35 seconds after the Big Bang, we send people on expensive expeditions to the South Pole to collect data, and we’re moved by the results they come up with, because curiosity is deeply embedded in our biology.