"power dynamic operates in emotional contagion, determining which person's brain will more forcefully draw the other into its emotional orbit. Mirror neurons are leadership tools: Emotions flow with special strength from the more socially dominant person to the less. One reason is that people in any group naturally pay more attention to and place more significance on what the most powerful person in that group says and does. That amplifies the force of whatever emotional message the leader may be sending, making her emotions particularly contagious. As I heard the head of a small organization say rather ruefully, "When my mind is full of anger, other people catch it like the flu."