It is estimated that there are more than 500 numeratives in modern Japanese. This presentation is going to analyze what kind of cognitive activities are working when a native speaker picks an appropriate numerative out of the vast list of morphemes. For example, “-hiki” is a numerative used when we count creatures in general, such as insects, fish, reptiles, small mammals, and even bacteria. Bigger mammals, such as elephants, horses, and whales are preferred to be counted with “-tou”, while we have collected several examples which allow the use of “-tou” to count beetles, butterflies, and small mammals. It proves that speakers see some common features between elephants and beetles when they count. As our conclusion, we showed the cognitive frameworks which erre filtering the morphological application of numeratives in Japanese, and considered the cultural backgrounds affecting them.