All across Africa, the Pacific and the Americas, we find cultures that didn't know about mouth kissing until their first contact with European explorers. And the attraction was not always immediately apparent. Most considered the act of exchanging saliva revolting.

During the Middle Ages they understood that words accompanied by imagery are much more memorable. By making the margins of a book colorful and beautiful, illuminations help make the text unforgettable. It's unfortunate that we've lost the art of illumination.

Back when I lived in Brooklyn, I'd sometimes take the Q train all the way out to Coney Island and back, and work on my laptop. There's something about pushy New Yorkers looking over your shoulder that really makes you produce sentences.

How much are we willing to lose from our already short lives by losing ourselves in our Blackberries, our iPhones, by not paying attention to the human being across from us who is talking with us, by being so lazy that we're not willing to process deeply?

If you were a medieval scholar reading a book, you knew that there was a reasonable likelihood you'd never see that particular text again, and so a high premium was placed on remembering what you read. You couldn't just pull a book off the shelf to consult it for a quote or an idea.

What makes things memorable is that they are meaningful, significant, colorful.

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.