The reason children
require a number of years to develop mastery of certain basic concepts, according to some child psychologists, is not that they are slow in learning the words — they actually know the words quite early — but that they have to start experiencing the world in a new, more simplified way that corresponds with the classifications suggested by these words.4 For example, young children may know the words
spoon, teaspoon,
silver, knife, and metal but find it difficult for several years to apply them appropriately to objects in their environment, the reason being partly that these words form multiple and overlapping classifications.