Think metaphorically of the information on a computer screen. It's only a very small part of the immense amount of data stored in the computer's files and in accessible Internet sites. The computer screen, like our working brain, contains only the information of current interest.

As I work on this column, I have visual access to about three paragraphs – which is about all I currently need and want as I write, edit, and move text. A few minutes ago, I scrolled back to the beginning to find out if I had already written a thought that entered my mind, and then I scrolled to the end to add a resource I thought readers might find helpful. I also retrieved, temporarily superimposed, and read filed information I thought I could use — a recent article I wrote and another file of summarized memory research. And then suddenly, the you have mail notice popped up at the top of the screen, and I briefly abandoned this project to read and briefly respond to a query from a friend. Before returning to this column, I spent 30 minutes looking through several books in my print collection for information I might use...

I trust you get the idea. The immediate focus of my attention was what was on the screen, but I could easily move in time and space to related and unrelated stimuli and media and come back to where I was. My computer is thus an electronic notebook that supports and simplifies the writing efforts of my working brain – and its excellent file system and search engines expedite the rapid retrieval of needed information.

I can effectively operate my computer, but most folks (including me) have to admit that we don't know how or where a computer stores and retrieves all the information it contains.

Similarly, although we effortlessly use our memory, where and how our brain stores and retrieves it is still an enigma (although theories certainly abound). Our frontal lobes apparently select and assemble the various information units involved in comprehension and response. Goldberg (2001) reports that our prefrontal cortex (behind our forehead) is directly interconnected with every distinct functional unit of our brain, and so it integrates most brain functions. It's often metaphorically called our brain's CEO for its key role in determining what's currently important and what to do about it.