Asymmetric number attraction effects have been typically explained via a privative markedness account: plural nouns are more marked than singular ones and thus stronger attractors. However, this account does not explain results from tripartite systems, in which a third number value is available, like paucal. Here we tested whether attraction effects can be driven by specific markedness sub-components, such as frequency/naturalness of use, using Serbian, in which participles can agree with masculine subjects in singular, plural and paucal. We first conducted a naturalness judgment task, finding the following naturalness/frequency pattern: singular,plural<paucal. In a subsequent forced-choice task, we presented participants with preambles containing a singular, a plural or a paucal headnoun (the castle[Sg] /two castles[Pauc] /the castles[Pl]) modified by singular/plural/paucal attractors (with the window[Sg] /with two windows[Pauc] /with the windows[Pl]). Three options were provided to complete the sentence (resembles[Sg] /resemble[Pauc] /resemble[Pl] gothic architecture).Both accuracy and reaction times (RTs) were collected. Accuracy data reflected the naturalness/frequency pattern, with paucal being the strongest attractor, and plural and singular attracting equally. However, reaction times showed a difference between singular and plural, suggesting co-influence of both frequency/naturalness and morphological markedness. We emphasize the necessity of re-defining markedness and testing attraction through different markedness sub-components (i.e. frequency/naturalness) to explain attraction cross-linguistically.