http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0016782
Here's a fascinating paper by Lera Boroditsky about how subtle metaphors influence the way we think about situations. Iirc, participants were asked to read a sentence about crime; in some versions, crime was described as a "virus", and in others crime was described as a "beast". People were then asked how they would stop the crime; the people who heard the different metaphors responded in different ways, but they were not conscious of how much the metaphor had influenced their response.
There's plenty of experimental work about how humans make poor judgments and decisions, but I haven't yet found much about how humans make poor judgments and decisions because of confusions about words. And yet, I expect such errors are common — I, at least, encounter them frequently.
It would be nice to have some scientific studies which illustrate the ways in which confusions about words affect everyday decision making, but instead all I can do is make philosophical arguments and point people to things like Yudkowsky's 37 Ways That Words Can Be Wrong or Chalmers' Verbal Disputes and Philosophical Progress.
Which keywords do I need to find experimental work on this topic? I tried Google scholar searches like "fuzzy concepts" "decision making" and effect of connotations on choices but I didn't find much in my first hour of looking into this.