The Middlemost Choice on Attitude Items

If respondents to a Thurstone-type attitude scale can make a middlemost response, in addition to agreement or disagreement, what concept underlies such responses when they are made? Ambivalence, neutrality, and uncertainty are three processes that can determine choice of the middlemost response. Definitions reflecting one of these processes or an innocuous control definition were presented to subjects as appropriate for a middlemost response on each of two attitude scales. The definitions presented differentially affected use of the middlemost response on one of the two scales. On that scale, an ambivalence definition yielded the greatest use of the middlemost response and differed from an uncertainty definition, which yielded the least use.