We have collected experimental evidence from a quantity judgment task to evaluate two theoretical claims on Mandarin classifiers (Cheng &Sybesma 1998, 1999; Zhang, 2013). Methodologically, we diverge from previous word extension tasks and avoid potential confounds, by turning to quantity judgment paradigm and directly testing for the quantificational standards participants use. Theoretically, our results support Cheng & Sybesma's view that Mandarin count classifiers individuate and specify reference to objects, while mass classifiers select substances. Mandarin morphosyntax reflects the object/substance distinction via classifiers.