  Words often convey affect -- emotions, feelings, and attitudes. Further,
different words can convey affect to various degrees (intensities). However,
existing manually created lexicons for basic emotions (such as anger and fear)
indicate only coarse categories of affect association (for example, associated
with anger or not associated with anger). Automatic lexicons of affect provide
fine degrees of association, but they tend not to be accurate as human-created
lexicons. Here, for the first time, we present a manually created affect
intensity lexicon with real-valued scores of intensity for four basic emotions:
anger, fear, joy, and sadness. (We will subsequently add entries for more
emotions such as disgust, anticipation, trust, and surprise.) We refer to this
dataset as the NRC Affect Intensity Lexicon, or AIL for short. AIL has entries
for close to 6,000 English words. We used a technique called best-worst scaling
(BWS) to create the lexicon. BWS improves annotation consistency and obtains
reliable fine-grained scores (split-half reliability > 0.91). We also compare
the entries in AIL with the entries in the NRC VAD Lexicon, which has valence,
arousal, and dominance (VAD) scores for 20K English words. We find that anger,
fear, and sadness words, on average, have very similar VAD scores. However,
sadness words tend to have slightly lower dominance scores than fear and anger
words. The Affect Intensity Lexicon has applications in automatic emotion
analysis in a number of domains such as commerce, education, intelligence, and
public health. AIL is also useful in the building of natural language
generation systems.
