There is an abundance of advice out there about how to become the world's best kisser. The reality is kissing is extremely variable. People prefer different styles of kissing at different times and, since everyone does so in their own way, our techniques may change depending on our partner. Science has only just touched upon this complicated subject, but one bombshell we've found is that kissing may not be as essential to coupling as many of us believe. "Romantic kissing is more erotic and much more part of the developed sensuality than just a simple, everyday expression," says William Jankowiak, professor of anthropology at the UNLV. This act, which seems so natural, may actually be a recent development in human history.