Kissing could have begun as a way of sniffing out who's who. From a whiff to a kiss was just a short trip across the face.

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.

I have never been particularly good with languages. Despite a dozen years of Hebrew school and a lifetime of praying in the language, I'm ashamed to admit that I still can't read an Israeli newspaper. Besides English, the only language I speak with any degree of fluency is Spanish.

If you want to live a memorable life, you have to be the kind of person who remembers to remember.

One trick, known as the journey method or 'memory palace,' is to conjure up a familiar space in the mind's eye, and then populate it with images of whatever it is you want to remember.

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.

Over the last few millennia we've invented a series of technologies - from the alphabet to the scroll to the codex, the printing press, photography, the computer, the smartphone - that have made it progressively easier and easier for us to externalize our memories, for us to essentially outsource this fundamental human capacity.