We use computational linguistics tools ("word embeddings") to map out a dimension for emotion on one pole and cognition on another pole.
The resulting geometric emotion scale is continuous and doesn't rely on the presence of particular words. In a human validation where annotators ranked pairs of sentences as more or less emotive, our metric agreed with human judgment much more often than a word-based measure.
We then apply the measure to the transcripts of 156 years (!) of speeches in U.S. Congress (1858-2014).
Emotional expression spikes during times of war, and has been mostly increasing -- especially since ~1979.
What happened in 1979? @cspan started televising Congressional Floor Debates!
Emotion is highest for a patriotism topic, foreign policy, and social issues. It is lowest for procedure, a government organization topic, and fiscal policy.
We also compare the parties. In fiscal policy speeches (those related to taxes and redistribution), Republicans are 2.5x more emotional than Democrats!
Republicans use emotion, rather than logic, to defend inequality-increasing policies.