If you've read thus far, you already know a lot about Dr. Carl Marci's brain. Now it's time to find out what's on his mind. As is our custom, we like to end each guest-edited issue of MEDIA with an "exit" interview, downloading their experience and any second thoughts they may have had. Unlike past editors - who have run the gamut from veteran consumer magazine editor Bob Guccione Jr. to Madison Avenue honchos like Alex Bogusky, Dale Herigstad and David Skokna - Marci is a scientist and a practicing doctor (in the field of psychiatry). But he also is …

In the year since Dale Herigstad guest-edited MEDIA, a lot has changed. Apple's iPad, which was just then being introduced to the marketplace, has spawned a revolution in tablet computing and content publishing, too. And Herigstad has moved from being chief creative officer of Schematic to CCO of Possible Worldwide, a new umbrella organization within parent WPP, which combined Schematic with its other best-in-breed interactive and design shops.

Without the contributions of Thomas Alva Edison, it's been said, we'd all still be in the dark. America's inventor-philosopher lit the way into the 20th Century, contributing so much to the framework of technological innovation that has brought us blazing into the 21st, up to and including, if not outright inventing electronic, screen-based media.

"I am writing a story about how our brains perceive and process content across various media screens and I can't help thinking about what my brain is doing at this very moment, even as the words I write appear on the screen of my computer. Or, for that matter, what your brain will do when you read them in this magazine or on some of the screens this story will eventually appear on."

A screen is defined as a surface where pictures can be projected for viewing. This term is not just related to media, it defines it; the screen is the membrane that "mediates" or stands between, an image and the individual viewing it. What happens without a literal screen? That image simply pipes directly into our mind's eye so that we can "see" it in the same way we "see" a dream.

We live in a world that is defined by the screens we watch or interact with. But unless you are using one to read this article, I'd like to ask you to put down your smartphone, turn off your iPad or simply turn away from your PC or television set and dwell on this remarkable fact: It has only been a little over 100 years since humans first began looking at screens. In evolutionary terms, that's barely the blink of an eye.

Imagine you're sitting at home watching television after a long day at work or taking care of the kids. You You are enjoying your favorite crime drama, basking in the realization that someone else's life truly is worse than your own. As the mirror neurons in your brain fire in the escapism of the rescue fantasy that the detective story line triggers - after all, in a world of terrorism and orange alerts, don't we all want to be a little safer? - your experience is suddenly interrupted by a commercial break featuring an ad for a chocolate brand. And …

The way people use media - especially screen-based media - has been shaped by advances in the science of computing and occasionally, in science fiction. That's a life imitating art fact. Remember the scene in Steven Spielberg's adaptation of Philip K. Dick's Minority Report, in which Tom Cruise's character was standing in front of a transparent screen, moving objects around using nothing but his hand gestures. Geeks like me were thrilled to imagine ourselves using such an interface in the distant future.

As a native New Yorker, I experience the neon tourist farm that is Times Square in a variety of ways: as a churl, as a misanthrope, as a hater of all animate beings in my midst. Even when the urge for culture strikes me and I slip into the genteel guise of a "thee-AY-turr" attendee, I rarely hesitate to plow through the neighborhood's chorus lines of slow-walkers, Red Rover-style. What I don't do during my infrequent Times Square forays is bend to the will of the bombardment of marketing. Obviously one can't completely ignore the shiny, blinky displays that beam …

On a recent weekend, my wife and I drove to the suburbs to see a movie in a new, "premium experience" theater. We sat in balcony seats and as I leaned forward, gazing on the crowd below, a single feature captured my imagination. It wasn't the ornate fixtures or the grand velvet curtain that would soon be pulled back to reveal the big silver screen. It was the vast sea of tiny flickering smartphone screens, glowing like a bioluminescent algae bloom in the darkness below.