Sensitive Periods are among the distinctive phases that occur for children within the First Plane of Development from birth through around age 4.5 to six years (exact timing depends on the specific sensitivity and the child). During this unique and limited time, the child is unconsciously drawn to activities that stimulate a specific phase of their development, and when un-thwarted, result in the healthy acquisition of that particular physical or psychological development.

The four characteristics of the child’s Sensitive Periods are:

1. They provide the motivation for a specific aspect of human development.
2. Internal mental growth precedes external manifestation of activity.
3. They are unconscious; the child is completely unaware of them.
4. They are temporary windows for optimal development.

Doctor Maria Montessori related this phenomenal period, in which children temporarily and unconsciously follow an internal need to a particular area of development, to the early life stages of the Porthesia butterfly, as studied by Dutch biologist Hugo DeVries. DeVries observed that this particular insect lays its eggs on the darkest corners of the plant where the branch meets the stem. Once hatched, these tiny larvae can only eat and digest the distant and most tender ends of the leaves. The Porthesia larvae have a special sensitivity to light that is not found in other species of butterfly larvae. This is what draws them out of the dark corners to the bright, tender tips that they need to eat in order to survive. Shortly thereafter, they lose this specific sensitivity and are no longer affected by, or drawn to, the light in the same way. Though the larvae will eventually die if they are not able to follow what draws them towards the light, children can be greatly affected for the long-term if these temporary developmental needs are not met with an environment that allows for each Sensitive Period to flourish and develop to completeness. Order, movement, sensory perception, and language are particular Sensitive Periods that are present in the child beginning at birth and waning around 4.5 years of age, with language development being an exception and lasting beyond age 6.

In The Creative Development of the Child, Dr. Montessori wrote that, “order is a necessary basis for the construction of the intelligence.” During the child’s Sensitive Period for order, they are orienting themselves to their setting and situation. When a young child has had a consistent environment that has a certain degree of order, they are able to feel safe, secure, and happy with a sense of trust regarding all aspects of their environment; people, places, and things. If the child’s need for order is not met by some means, their resulting behavior may be seen as erratic, excitable, and problematic. This is when the notion of “the terrible twos” comes into play and is really not the fault of the child, but is a sign that something is lacking for vital development within the child’s environment. Especially around this age, the child’s need for order is so strong that even the smallest change in daily routine or unconscious expectations can have a detrimental effect that is overpowering and overwhelming to the child. They don't yet have the power to see beyond what we adults see as small, inconsequential details that are little to worry about; but to them, it is their whole being that can be affected by any change within their particular order. In our Montessori classrooms, we can support this Sensitive Period for order with regular routines as well as by encouraging the young child through work with the Practical Life materials. Here, there is an external order within the placement and sequence of materials that the children can rely on.

The Sensitive Period for Movement is present in children from birth to around 4.5 years old and can be separated in three parts relating movement to order, the will, and to intelligence. Order is connected to movement in this category because the child has to coordinate and organize the movements of their body beginning with reaching and rolling to walking and developing fine motor skills which all become necessary building blocks for further development to take place. Dr. Montessori refers to a necessary pattern for the development of any natural movement. She says you must first prepare the “instrument” of the hand or body for movement, strengthen the instrument through activity, take in images from the environment that relate to that particular movement, imitate that observed movement, and then finally internalize and personalize the movement. By around age 3, when children enter our Montessori primary environments, they are refining their equilibrium and locomotion as well as fine motor skills and manual dexterity. The child’s movement and will corresponds to how they create their own relationship with their mind and body. The will of the young child is at first unconscious, but then becomes deliberate and with specific intentions. In The Absorbent Mind, Montessori reminds us that “watching a child makes it obvious that the development of his mind comes about through his movements.” Movement and intelligence are associated within this period in the way that the hand is a tool of the mind and helps connect it to the environment. The Sensitive Period for movement guides the child to integrate body and mind, creating a perfect harmony with an eye that sees and a hand that obeys.

The development and refinement of sensory perception and language are the last two Sensitive Periods that children within our primary communities experience. Both of these Sensitive Periods begin at, or before, birth but the refinement of sensory perception persists until around 4.5 years of age, while the Sensitive Period for language continues to be vital and develops beyond the age of 6. Sensory perception is an internal development that can only grow when the child is allowed to dynamically interact with, and be involved in, their environment. Through these interactions, children create their own way to classify their sensory perceptions and from that can form abstractions within their active mind. Because of the great importance of this somewhat hidden Sensitive Period, Maria Montessori created the Sensorial area of the primary classroom so the children could be free to explore and grow through their senses of sight, touch, sound, smell, and taste, as well as vestibular and proprioceptive senses.

The Sensitive Period for language takes the longest to complete and can be broken down into 2 sub-phases, pre-linguistic and linguistic. During the pre-linguistic phase, the infant is preparing for speech by absorbing all the sounds and idiosyncrasies within their environment while practicing the face and mouth movements needed for speaking. This sub-phase typically lasts until around 10-12 months of age. The linguistic phase spans from 1-3 years of age and is characterized by the use and progressive development of sounds, then words, then phrases, then well thought out sentences. In The Secret of Childhood, Montessori writes, “in the beginning, the sounds of the environment are confusion and chaos, indistinguishable and then, all at once, the mind, as yet without thought, hears a kind of music that fills the world. Then the very fibers of the baby are stirred…and a new rhythm is prepared for the cosmos.” Although there is a dedicated area for language activities in each of our primary environments, language is actually present within all aspects of the classroom and the environment as a whole. This period is not only vital for the proper development of speech and writing, but for proper progress throughout life.

In our role as guides at Three Tree Montessori, we strive to be able to recognize the behaviors and characteristics displayed by each of the children so that we can ensure that our environments are suited for their individual needs and sensitivities. Sensitive Periods can be recognized through a series of actions displayed by the child’s particular order, including an irresistible urge towards a particular activity in the environment, great distress if the activity is thwarted, repetition of the activity which leads to concentration, and evident satisfaction and joy at the completion of the activity. Incredibly, after the need has been met, there is generally complete indifference to what was once irresistible. As your child’s guide begins to notice these behaviors, we respond appropriately with rich activities for each child to engage in that can fully support all of their developmental and physical needs within their Sensitive Periods.

Meagan Johnson, TTMS Children's House Guide

April 2023