From the article:
"This is going to be all about dealing face-to-face (or voice-to-voice or text-to-text) with real live people and exploiting the natural tendency to trust.
Of course, this skill underpins everything else that we do when on a social-engineering engagement - in order to impersonate a UPS guy, talk someone out of their password, write a great targeted phishing email, or know exactly where to drop the USB keys - you have to have great skills at exploiting the natural tendencies of humans.
This means a deep understanding of the three fundamental skills (that I have mentioned often in introductory talks and articles on this topic) - the ability to communicate, the ability to be aware of your surroundings, and your ability to control the context (or "cognitive frame") of your interaction."
Human 0days are promised in the future!