Our lives are the sum of our memories. How much are we willing to lose from our already short lives by … not paying attention?

Over the last few millennial, we've invented a series of technologies … that have made it progressively easier and easier for us to externalize our memories, for us to outsource this fundamental human capacity.

Once I'd reached the point where I could squirrel away more than 30 digits a minute in memory palaces, I still only sporadically used the techniques to memorize the phone numbers of people I actually wanted to call. I found it was just too simple to punch them into my cell phone.

Many memory techniques involve creating unforgettable imagery, in your minds eye. Thats 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.

'Moonwalking with Einstein' refers to a memory device I used when I memorized a deck of playing cards at the U.S. Memory Championship. When I competed in 2006, I set a new U.S. record by memorizing a deck of cards in one minute and 40 seconds. That record has since fallen.

What distinguishes a great mnemonist, I learned, is the ability to create lavish images on the fly, to paint in the mind a scene so unlike any other it cannot be forgotten. And to do it quickly. Many competitive mnemonists argue that their skills are less a feat of memory than of creativity.

With our blogs and tweets, digital cameras, and unlimited-gigabyte e-mail archives, participation in the online culture now means creating a trail of always present, ever searchable, unforgetting external memories that only grows as one ages.

The art and science of memory is about developing the capacity to quickly create images that link disparate ideas. Creativity is the ability to form similar connections between disparate images and to create something new and hurl it into the future so it becomes a poem, or a building, or a dance, or a novel. Creativity is, in a sense, future memory.

I met with amnesiacs and savants, educators and scientists, to try to understand what memory is, why it works, why it sometimes doesn't, and what its potential might be.