Maria Montessori observed that there are phases in which children are particularly open to specific experiences. During these periods, the child's attention is focused on particular aspects of their environment. It learns certain skills in these areas with enthusiasm and ease, which at other times it could only acquire with much effort and intentional exertion.
Montessori recognized that each child can learn and work according to their temperament and inner rhythm. She categorized this receptiveness to experiences into four timeframes, which she called "sensitive periods." The age range should be seen as approximate, not static.
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1. Period of Construction (0-6 years) - Children's House
This phase is also referred to as "The Absorbent Mind." During this period, the child is highly sensitive to the development of motor skills, sensory perception, language, and orderliness. The daily routine, materials, and spatial organization of the Children's House provide appropriate learning and developmental stimuli, promoting both gross and fine motor skills and tailored to sensory and language development.
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2. Period of Refinement (6-12 years) - Child's School
In the second developmental phase, children's sensitivity to experiencing the real world, developing abstraction skills, conscience, and morality is particularly heightened. Children of this age show a strong desire to understand the interconnectedness of the world and to explore and comprehend the reasons for existence. They seek to reexperience moral judgments such as "good and evil" in communal living. In the school, interdisciplinary learning in various social forms and working with real materials take center stage.
​3. Period of Transformation (12-18 years) - Earth Children
This developmental phase is characterized by the adolescents' need to develop self-confidence through creative activity on one hand, and on the other hand, to experience protection and belonging within a social community (peer group). The individualization of their own person may be accompanied by a strong separation from parts of the social environment.
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4. Maturation (18-24 years) - School of Experiential Social Life
In the fourth developmental phase, the personality of the youth matures. They refine the ability to make decisions and take responsibility for their consequences. The acquired knowledge is used to care for themselves and others. They gain the potential to start their own families.