It is commonly believed that objects in the world can be categorized in at least three different ways or levels. The three levels are basic, superordinate, and subordinate. Previously it was believed that basic categorization presents a cognitive (mental) advantage to children's development. However, recent studies on superordinate categorization has challenged this belief.

1. Items in superordinate are grouped according to functional purpose, even though they may not share any similarities in how they look (perception). For instance, desks, chairs, and beds do not appear similar but they can be group together in the superordinate category of furniture.
2. Items in basic categorization share similarities in function and in perception. For instance, chairs can be considered as a basic category. Chairs can share functional and perceptual similarities with many kinds of chairs but are readily distinguished from other types of furniture like beds or desks.
3. Subordinate categories are subsets of basic categories. For instance, kitchen chairs, desk chairs, and high chairs, are all within the basic category of chairs. Each one is very similar in it's function to the others but is definitely discriminable.

This study was developed to investigate the development of categorization at all three levels by using a design in which children between the ages of 1 and 3 years are tested for categorization at all three levels with sets of objects from the same domain (such as vehicle or fruit). Researchers plan to chart when infants develop categorization at the basic, subordinate, and superordinate levels over the two-year period.