The variables define any 'scientific' study. In this case, the symbols must be neutral in content or connotative meaning, or else noting them with speed would be a reflection of imprinted meaning rather than simple focus. The use of the letter W on politically minded Americans is hardly a neutral path. 'W' over the last years has gathered huge significance, particularly to the left. Oddly, the study showed NO significant difference between conservatives and liberals on the letter M. Such a significant change must be explained before any conclusions can be reached, since it implies an unknown factor in the variable itself.

Yeah, I posted about this elsewhere. Googling the letter "W" will bring you to a results page that lists George W. Bush's Wikipedia entry ranked at #5, and a White House page about George W. Bush at #6. Now, google hate + W, and the top entry on the page is thetruthaboutgeorge.com. Shuffle through a few pages and you'll see something about George W. Bush on each page. If you're going to conduct a politically oriented study, using the letter W indicates that you're not necessarily looking for neutral results.