Montessori also developed an area of curriculum called “sensorial” for the Montessori classroom. In 1967, Montessori said she drew upon her psychological testing and objects as well as materials “…earlier designed in her [own] experimental work.”

She also used material by other educators as they attempted to educate mentally deficient children. The sensorial materials were developed to help children in the process of creating and organizing their intelligence. As the child becomes more adept at using his senses, he begins to enjoy his world more and, as a natural result, engages in even more exploration and development.

Montessori categorized Sensorial exercises into eight different groups: visual, tactile, baric, thermic, auditory, olfactory, gustatory, and stereognostic. Visual exercises help develop the child’s ability to visually discern differences between similar objects, while tactile exercises teach through the sense of touch. If the child is only experiencing the tactile sensation through one small part of his body, he can better focus on what he is feeling. In baric exercises, the child learns about pressure and weight, while in thermic exercises he works to refine his understanding of temperature. Auditory exercises aid the child in discerning between different sounds, while olfactory and gustatory exercises help the child distinguish smells and tastes. Finally, in stereognostic the child learns to recognize objects through feel.

Why do we have the sensorial area in the Montessori classroom? Each lesson in the sensorial area is designed to emphasize one quality, but in different degrees that are perceptually observable; the quality being focused on is found in the world and may include size, shape, or color. Unlike the zippers and bows used in practical life exercises, the materials used here are not those encountered in everyday life.

Sensorial materials offer self-correction so that the child can focus on this one isolation of difficulty. (That is, the mistake made is easily identifiable and the child will see it and correct it himself, rather than turning to the teacher.) As a result of self-correction, the child gains auto-education from the lessons given. The sensorial materials help the child to distinguish, to categorize, and to relate new information to what he already knows; they are not meant to introduce new, potentially confusing information to the child.

Children in the age three to six classroom arrive with many “sensitive periods” for the sensorial area, meaning that in a certain phase of development they are particularly drawn toward and receptive to certain forms of learning. Montessori created the sensitive period for order. Here, the child finds a sense of order in the materials and obtains a joy for learning while his environment is orderly. Second is the sensitive period for the refinement of the senses.  Montessori said, “The education of the senses has, as its aim, the refinement of the differential perception of stimuli by means of repeated exercises.”