Valence Shifting: Is It A Valid Task?

This paper looks at the problem of valence shifting, rewriting a text to preserve much of its meaning but alter its sentiment characteristics. There has only been a small amount of previous work on the task, which appears to be more difficult than researchers anticipated, not least in agreement between human judges regarding whether a text had indeed had its valence shifted in the intended direction. We therefore take a simpler version of the task, and show that sentiment-based lexical paraphrases do consistently change the sentiment for readers. We then also show that the Kullback-Leibler divergence makes a useful preliminary measure of valence that corresponds to human judgements.