The Secret of Socrates - From Dale Carnegie

We may begin the conversation with an open-probe question and people say “Yes” at the outset, leading them in the affirmative direction. Interesting part is the psychological patterns. When a person says “No” and really means it, he or she is doing far more than saying a word of two letters. The entire organism – glandular, nervous, muscular – gathers itself together into a condition of rejection. The whole neuromuscular system, in short, sets itself on guard against acceptance. To the contrary, when a person says “Yes”, the organism is in a forward-moving, accepting, open attitude. That, what is buried far underneath the surface is much important than the appearance, is the point.