In the Montessori Approach, these planes of development are seen as driving behavior in very stage of development, and education should respond to and facilitate their expression.
From birth to six years of age is the first plane. During this period, Montessori observed that the child undergoes striking physical and psychological development. The first-plane child is seen as a concrete, sensorial explorer and learner engaged in the developmental work for psychological self-construction and building independence.
Acquisition of language – from birth to around 6 years old
Interest in small objects – from around 18 months to 3 years old
Order – from around 1 to 3 years old
Sensory refinement – from birth to around 4 years old
Social behavior – from around 2 1/2 to 4 years old