  Emotion dynamics is a framework for measuring how an individual's emotions
change over time. It is a powerful tool for understanding how we behave and
interact with the world. In this paper, we introduce a framework to track
emotion dynamics through one's utterances. Specifically we introduce a number
of utterance emotion dynamics (UED) metrics inspired by work in Psychology. We
use this approach to trace emotional arcs of movie characters. We analyze
thousands of such character arcs to test hypotheses that inform our broader
understanding of stories. Notably, we show that there is a tendency for
characters to use increasingly more negative words and become increasingly
emotionally discordant with each other until about 90 percent of the narrative
length. UED also has applications in behavior studies, social sciences, and
public health.
