In short, coordination of moods is the essence of rapport, the adult version of the attunement a mother has with her infant. One determinant of interpersonal effectiveness, Cacioppo proposes, is how deftly people carry out this emotional synchrony. If they are adept at attuning to people’s moods, or can easily bring others under the sway of their own, then their interactions will go more smoothly at the emotional level.
