  Word-level saliency explanations ("heat maps over words") are often used to
communicate feature-attribution in text-based models. Recent studies found that
superficial factors such as word length can distort human interpretation of the
communicated saliency scores. We conduct a user study to investigate how the
marking of a word's neighboring words affect the explainee's perception of the
word's importance in the context of a saliency explanation. We find that
neighboring words have significant effects on the word's importance rating.
Concretely, we identify that the influence changes based on neighboring
direction (left vs. right) and a-priori linguistic and computational measures
of phrases and collocations (vs. unrelated neighboring words). Our results
question whether text-based saliency explanations should be continued to be
communicated at word level, and inform future research on alternative saliency
explanation methods.
