Last week, the Human Connectome Project, supported jointly by sixteen components of the National Institutes of Health, released its first set of data, a massive set of structural and functional images of the brains of sixty-eight adult volunteers—to almost no fanfare whatsoever. The amount of data, two terabytes, is so great that it poses problems for the Internet; you can download it for free if you like, but the organizers of the project would rather mail it to you on a hard drive.

The announcement has received so little press so far because nobody has yet figured what to do with all the data. In principle, data of this sort might contribute to understanding how the brain works, and might have important implications for treating neurological disease—especially when the project is complete, and the researchers have scanned all one thousand two hundred subjects. But, for now, we know how much data has been collected, but not what it all means.

If I were in the Obama Administration, I would be worried. According to a recent report in the New York Times, the Administration is about to submit a three-billion-dollar request to Congress to support something called the Brain Activity Map. Congress might well wonder why they should invest in yet another brain project if the first stage of the Human Connectome Project hasn’t yielded immediate fruit.

Fortunately, a study of the thing that the Brain Activity Map seeks to measure—the activity of billions of individual neurons, measured simultaneously—is entirely unprecedented, absolutely necessary, and vastly more fine-grained than the target of the Human Connectome Project. The latter has been looking at the interconnections between roughly five hundred “brain areas”; Obama’s Brain Activity Map is focused on a much more detailed level. The Human Connectome Project is like a plan to figure out broad strokes of the United States economy by mapping the cities that people and goods travel through. The Brain Activity Map is more like an effort to figure out the economy by examining the dynamics of individual consumers. Both projects have value, but their contributions are different, if complementary.

Still, although there is little risk of overlap between these two projects, the Obama Administration would do well to reflect on what the Human Connectome Project has discovered so far: it is easier to collect massive amounts of data than to understand them.

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In the history of science, there has always been a balance between empirical and theoretical research—between collecting data and trying to understand the deeper factors that explain those data. Sometimes a single person or group is responsible for both, such as when Archimedes observed some data (water spilling out of his bathtub) and developed a preliminary understanding of a new theory, hydrostatics. In modern times, scientific advances often rely on two separate sets of researchers. In physics, for example, some people specialize in developing intricate machinery to track elusive particles, while others develop theoretical tools for interpreting those data.

The focus of the Brain Activity Map project is primarily on developing new techniques for gathering data. Its goal is to create national neural observatories, places where neuroscientists will be able to collect high-quality neuron-by-neuron brain data from laboratory animals, and perhaps eventually humans. Much as astronomers can book time on the Hubble Space Telescope, neuroscientists will be able to book time to see, with enormous clarity and detail, animal brains.

Nevertheless, when the Administration puts forward its research plan, it should not neglect theoretical research. Sometimes people collect the data before they are able to develop good theories, but the best experiments are often ones that help scientists sift through competing theories. Unfortunately, in two preliminary proposals in the scientific journals (Neuron and Science), there has been relatively little discussion of what specific hypotheses will be tested, or how, with just a few words written so far about how to interpret the “data deluge” that is to come.

Before the Administration submits its formal proposal to Congress, it needs to incorporate more voices into the planning. Right now, the steering committee consists largely of experimental neuroscientists and nanotechnologists; there needs to be many more theoretical neuroscientists, as well as cognitive psychologists, experts in animal behavior, and perhaps even a philosopher or two. (How, for example, is it that a bunch of firing neurons gives rise to our inner experiences?)

Understanding the brain will require us to develop new understandings of the brain’s connectivity patterns (both micro and macro), the dynamics of individual neurons and the circuits that connect them, and the ways the brain encodes information. To make sure that the Brain Activity Map yields true insights into these questions, theorists need to be equal partners with data collectors, deeply involved from the outset.

In a previous essay on this topic, I suggested five specific goals: understanding the language of the brain, understanding how neurons organize into circuits, understanding how the brain develops and learns, understanding how the brain determines which circuits to use in a given situation, and understanding the relations between neural circuitry and behavior. The Brain Activity Map has the potential to speak to each of these questions, but its advocates need to say much more about how the data they collect will be used to address theoretical questions. Obama’s grand challenge shouldn’t be to record data from every neuron, per se, but to understand how the brain works. The Brain Activity Map is a means to an end, but not the end in itself.

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After I wrote about the Obama proposal a few weeks ago, lots of people in the media approached me for comment. Most seemed to be looking for a simple either/or: should we fund the proposal or shouldn’t we? But the question before us is not binary. We absolutely should invest in neuroscience, quite possibly even more—but the real question should be how to maximize that investment.

Gary Marcus, scientist and author of “Guitar Zero,” has written fifteen essays for The New Yorker, on topics such as Noam Chomsky, Nate Silver, Ray Kurzweil, and pivotal challenges in neuroscience, robotics, and artificial intelligence.

Illustration by Jordan Awan.