Planes of Development

Toddler and Primary environments serve the first plane of development, the Lower and Upper Elementary classrooms serve the second plane of development, and the Junior Class marks the beginning of adolescence and the third plane of development. The accuracy in this description is apparent if we look at the greater difference between Primary and Lower Elementary students or between Upper Elementary and Junior students. Conversely, the difference between Lower and Upper Elementary classrooms is much smaller.
Further, Montessori described the planes in broader terms. A strong sense of order marks the first plane. We certainly see this reflected in both the children’s activities (sorting, lining up objects, and differentiating items) and the curriculum (sensorial materials and practical life). The second plane is marked as an explosion into the social realm. The methodical 5-year-old morphs into the rambunctious 6-year-old. The Upper and Lower Elementary classrooms meet this need with more group work, more collaboration, and more opportunity for social interaction. The third plane in many ways mirrors the first, as an egocentric phase that is given to tremendous brain growth. Junior students are looking towards adulthood, and their classroom gives them every opportunity to try on new adult roles.
Central to Maria Montessori’s view of an educational system that is child centered and developmental by definition, the planes of development put a structure of common characteristics and tendencies around human growth from birth to 24 years of age. Thus, Montessori observed that children appeared to change into new individuals about every 6 years. She reasoned that if the child developed anew, then it followed that the learning environment and the adults’ approach should also change. She stressed two points. First, if the child reached his or her full potential in the present plane, this created a firm foundation for the successive plane. Second, if the child did NOT realize his or her full development in one plane, he or she would still move into the next plane, but without the requisite academic and social skills. The first plane of development encompasses the years from birth to 6 years of age. Children from 6 to 12 years of age are in the second plane of development. Early adolescence to young adulthood (12 to 18 years old) is identified as the third plane of development. Finally, the 6 years between the ages of 18 and 24 constitute the fourth plane of development. In general terms, Montessori noted that the first and third planes are periods of tremendous transformation and construction, while the second and fourth planes are years of stabilization and strengthening. Each plane is also divided into two subplanes, each of 3 years in length.
Montessori schools are constructed and organized to support the kind of growth and learning that occurs within these developmental planes and subplanes. Toddler and Primary classrooms (first plane) share many like materials, lessons, and emphases, while still being distinct environments. The Elementary classrooms (second plane) represent a large change from the Primary years. While there are also significant differences between the subplanes of Lower and Upper Elementary classrooms, they are fewer and less salient. The Junior Class represents the first 2 years of the third plane of development and is another big jump. Knowing your child’s developmental plane is an important step in understanding his or her needs and setting appropriate expectations.