 On the other hand, proponents of prototype theory propose that count-classifiers may not have innate definitions, but are associated with a noun that is prototypical of that category, and nouns that have a "family resemblance" with the prototype noun will want to use the same classifier. For example, horse in Chinese uses the classifier 匹 pǐ, as in 三匹马 (sān pǐ mǎ, "three horses") — in modern Chinese the word 匹 has no meaning. Nevertheless, nouns denoting animals that look like horses will often also use this same classifier, and native speakers have been found to be more likely to use the classifier 匹 the closer an animal looks to a horse. Furthermore, words that do not meet the "criteria" of a semantic category may still use that category because of their association with a prototype. For example, the classifier 颗 (顆) kē is used for small round items, as in 一颗子弹 (yì kē zǐdàn, "one bullet"); when words like 原子弹 (yuánzǐdàn, "atomic bomb") were later introduced into the language they also used this classifier, even though they are not small and round — therefore, their classifier must have been assigned because of the words' association with the word for bullet, which acted as a "prototype". This is an example of "generalization" from prototypes: Erbaugh has proposed that when children learn count-classifiers, they go through stages, first learning a classifier-noun pair only (such as 条鱼 tiáo yú, CL-fish), then using that classifier with multiple nouns that are similar to the prototype (such as other types of fish), then finally using that set of nouns to generalize a semantic feature associated with the classifier (such as length and flexibility) so that the classifier can then be used with new words that the person encounters.
