If space and time are an issue, is there any way to assess ambivalence without having separate items for positive and negative valence toward the target?

It is fairly clear in research on attitudes that a neutral attitude (i.e., no opinion one way or the other) and an ambivalent attitude (i.e., equivalent positive and negative evaluations toward the same target) are different; however, how do we know whether a midpoint response (e.g., “4” on a 7- point scale, “0” on a –3 to +3 scale) is neutral for some people and ambivalent for others, particularly when there is no “ambivalent” response option? If space and time are an issue, is there any way to assess ambivalence without having separate items for positive and negative valence toward the target? Does any of this matter? Why or why not?