Measure 31 — MATH 6

Classification and Matching

Child shows increasing ability to compare, match, and sort objects into groups according to some common attribute

The ability to classify is a basic component of children’s developing concepts about physical and logical relationships. It is thought to be an important foundation for mathematics, particularly algebra. Preschool children demonstrate a developing understanding of classification by sorting and categorizing things into groups (or “classes”) based on some common property. The development of classification depends on being aware of the identity, similarities, and differences among the attributes of things, and then forming ideas about categories and class membership based on some common attribute. Across infancy and early childhood, children’s early ideas about the appearance and function of things they experience (what things are alike and what things are not alike) develop into the beginnings of logical classification.

From birth, infants attend and react to the people, objects, and events in their environment. They very quickly learn the sounds, sights, smells, and sensations of their immediate caretaking environment; and they relate differently to people, things, and events that are familiar versus the unfamiliar. They form associations between what something looks like and what it does based on their experiences, and they begin to form simple categories of things that look and/or behave in a particular way, such as “things that move when you bat at them.”

Toddlers demonstrate a growing awareness of the ways in which things, people, or events share common features or functions and, thus, belong together in some way. In their actions, toddlers begin to organize things in the environment according to recognized attributes. For example, they might put all toy animals in one corner of a toy shelf. They form simple sets of things by putting similar or identical things together (matching). For example, in playing with Duplo™ blocks, a child might put two red blocks together then put two blue blocks together.

The sorting behaviors of young preschoolers show a beginning understanding of the concept of class. They organize objects into groups by separating particular objects from a larger collection because they share a common attribute—for example, selecting out the horses from a collection of toy animals. However, the groups they form are not true classes, as they may not be clearly defined by what is included and what is excluded. Their sorting may be incomplete so that the group they produce does not include all the horses from the collection. Furthermore, they may change the basis on which they select objects. For example, after selecting out most of the horses, a child might add various other farm animals to the group.

The groups that older preschoolers produce when they sort a collection of objects demonstrate the beginnings of true classification. Typically, they can sort a collection of objects into two or more groups based on one attribute, such as shape, color, or function, using a consistent rule. A child might sort a collection of toy vehicles to form two groups: vehicles that are cars and vehicles that are not cars. With experience and development, children become increasingly flexible in their sorting behaviors, and they become able to sort a collection of objects in more ways than one. A child might sort a collection of objects by size and then re-sort the same collection by color or some other attribute. Eventually, children are able to sort collections of objects by more that one attribute at a time (sorting circles by color and size, for example). The sorting abilities of young children and their knowledge about classes continue to develop in early elementary school.