 For example, by showing how children progressively enrich their understanding of things by acting on and reflecting on the effects of their own previous knowledge, they are able to organize their knowledge in increasingly complex structures.Thus, once a young child can consistently and accurately recognize different kinds of animals, he or she then acquires the ability to organize the different kinds into higher groupings such as "birds", "fish", and so on.This is significant because they are now able to know things about a new animal simply on the basis of the fact that it is a bird – for example, that it will lay eggs.