One of the great challenges of our age, in which the tools of our productivity are also the tools of our leisure, is to figure out how to make more useful those moments of procrastination when we're idling in front of our computer screens.

When I climb into my car, I enter my destination into a GPS device, whose spatial memory supplants my own. I have photographs to store the images I want to remember, books to store knowledge and now, thanks to Google, I rarely have to remember anything more than the right set of search terms to access humankind's collective memory.

No one who set out to design a form of communication would ever end up with anything like English, Mandarin, or any of the more than six thousand languages spoken today.

No one who set out to design a form of communication would ever end up with anything like English, Mandarin, or any of the more than six thousand languages spoken today.

Our subjective experience of time is highly variable. We all know that days can pass like weeks and months can feel like years, and that the opposite can be just as true: A month or year can zoom by in what feels like no time at all.

Just as we accumulate memories of facts by integrating them into a network, we accumulate life experiences by integrating them into a web of other chronological memories. The denser the web, the denser the experience of time.

The fact that books today are mostly a string of words makes it easier to forget the text. With the impact of the iPad and the future of the book being up for re-imagination, I wonder whether we'll rediscover the importance of making texts richer visually.

Someday in the distant cyborg future, when our internal and external memories fully merge, we may come to possess infinite knowledge. But that's not the same thing as wisdom.

Our ability to find humor in the world, to make connections between previously unconnected notions, to create new ideas, to share in a common culture: All these essentially human acts depend on memory.

Many memory techniques involve creating unforgettable imagery, in your mind's eye. That's an act of imagination. Creating really weird imagery really quickly was the most fun part of my training to compete in the U.S. Memory Competition.