Dr. Montessori saw in her observations of children that certain sensitive periods occur; these sensitive periods are related to certain elements in the environment to which children are irresistibly drawn. Children are attracted only to certain elements in the environment for a short time, as one sensitivity recedes another sensitivity arises to take its place.  According to Dr. Montessori, during a sensitive period it is very easy for children to acquire certain abilities, such as language, discrimination of sensory stimuli, and mental modeling of the environment. 

 

The purpose of each sensitive period, which is actually an inner sensibility possessed by children, is to help them acquire a certain skill or characteristic necessary for their growth. As they acquire the skill or characteristic, their sensitivity for it decreases and another sensitivity increases.   All sensitive periods are related in that each provides a foundation for the next. Together, the sensitive periods help children to make sense out of what they and the work around them are all about. 

Maria Montessori discovered that the unrealized potential of the child's mind is one of the greatest secrets of childhood.  When the proper materials are made available in a prepared environment, children spontaneously acquire knowledge beyond what is generally thought to be possible for their age.  For example, if you look at the Sensitive Period for Reading, you might note that most children do not start 1st Grade until they are 6 years old.  By that time, the Sensitive Period for Reading is already past.  Similarly, the Sensitive Period for Language is from Birth to age 6.  Once the sensitive period for a particular ability is past, the development of the brain has progressed past the point at which information can be simply absorbed.  The child must then be taught the ability, resulting in expenditure of conscious effort, and not producing results as great as could be produced if the sensitive period had been taken advantage of.