This paper investigates how an interpreter resolves a particular type of ambiguities common in sketches, namely, the ambiguities as to what graphical variables (such as line width in sketched maps) are expressive and what are not. We hypothesize that a graphical variable is assessed to be non-expressive if it has a unified value throughout the sketch (e.g. all bands representing roads have the same width in the sketch). Our experiment, which analyzed interpretative decisions of human subjects on sketches, has in fact demonstrates such an unfiedness effect, although an interesting collection of exceptions were also found. We discuss the implications of these results, and offer the interpretation of the unfiedness effect as an evidence to the veristic disambiguation strategy.