From Tony Schwartz in NY Times: I once served on a committee led by a powerful woman. She had strong views, but what I remember most is that whenever I spoke, she nodded her head vigorously and affirmatively. Over time, I learned that her nodding didn’t mean she necessarily agreed with me. Even so, I always sensed that she was listening closely and carefully considering what I had to say.
Today I make my living in part by speaking to large groups. Instinctively, I find myself scanning the audience for beacons of affirmation — people whose positive body language makes me feel valued and energized. If I happen to alight on someone shaking his head negatively or looking distracted or bored, I feel a lurch in my stomach and a surge of defensiveness.