You are what you read.

That's true both literally and figuratively.

Literally, our brains are changed by the activity of learning to read.

Figuratively, our attitudes are shaped by the content of what we read.

Like all learning, learning to read changes our brains at the cellular level. Imagine your brain as a system of connecting airports. Busy airports with planes flying in and out all day are expanded to take care of the traffic; small regional airports with little or no traffic eventually close down.

In our brains, the "traffic" is in the form of electrical signals, and the airports are the individual brain cells, or neurons. When we learn something, we increase the electrical traffic and the neurons physically grow larger and denser to accommodate.

This growth and activity can be seen on MRI scans, and researchers have tracked our ability to read to one part of the brain located behind our left ear. In his newest book, "Reading in the Brain," French neuroscientist Stanislaus Dehaene points out that not only are our brains changed by reading, but reading has been designed to fit what our brains can already do.

As an activity, reading evolved a mere four thousand years ago - and Dehaene theorizes that humans have shoehorned reading into the part of the brain that can recognize certain types of visual cues. Other researchers have discovered that all alphabets of the world use the same three distinct strokes - the most that a single brain cell can recognize.

"What I am proposing is that the human brain is a much more constrained organ than we think, and that it places strong limits on the range of possible cultural forms," Dehaene writes in the November issue of Scientific American. "Essentially, the brain did not evolve for culture, but culture evolved to be learnable by the brain."

That's a big part of the discussion as our culture moves increasingly from print media to a digital information world. How is our biology determining how we will gather information in the future, and how will learning that information change our brains?

"A decline in both reading and reading abilities was clearly documented in the first generation of teenagers and young adults raised in a society full of videogames, cell phones, iPods, laptops, and other electronic devices," writes Dana Goia, chairman of the National Endowment for the Arts, in the 2009 comprehensive survey of reading habits in America. "Faced by a clear and undeniable problem, millions of parents, teachers, librarians, and civic leaders took action."

This year for the first time in the past quarter century, an NEA survey of 18,000 Americans shows that literary reading is on the upswing. The group that had shown the steepest decline in the past - 18-24 year olds - has shown the largest increase. Goia is cautious about assigning cause and effect, though he notes that young adults in this category were in high schools when the concerted effort to encourage reading by schools and libraries gained momentum.

Those new readers also demonstrate differences in their behavior that have been documented through regular surveys. Readers are more likely to be historically and politically aware than non-readers. They attend more arts and sports events, are more educated, participate in more outdoor activities, and volunteer for more charities. Whether reading happens with a paper book or online is irrelevant - the action of reading appears to have both personal and social benefits.

Our brains didn't evolve to learn to read, but they did evolve to learn through narrative, and that is why the work to preserve a culture of literacy is so important. We need stories - they help us make sense of our experiences and our surroundings. And more importantly, reading exposes us to experiences and surroundings not our own. Reading gives us a multitude of points of view to consider and gives us a window into the minds of others - it opens up our horizons to vistas larger than our own neighborhoods and presents us with ideas and visions we could not have imagined by ourselves.

And that is the most exciting reason I encourage my students to read - not just because doing so grows their brains or makes them into better citizens, but because reading pushes them into places they might not travel otherwise, around corners they would not navigate, over hills that from a distance look insurmountable. Through literature we are able to borrow the brains of authors who lived long ago or far away as well as those familiar and near, expanding our own understanding of an increasingly complex world.

Observer columnist Kay McSpadden is a high school English teacher in York, S.C., and author of "Notes from a Classroom: Reflections on Teaching." Write her at kmcspadden@comporium.net.