First, children and developing adults engage in psychological self-construction by means of interaction with their environments. Second, children, especially under the age of six, have an innate path of psychological development. Based on her observations, Montessori believed that children who are at liberty to choose and act freely within an environment prepared according to her model would act spontaneously for optimal development. Montessori saw universal, innate characteristics in human psychology which her son and collaborator Mario Montessori identified as "human tendencies" in 1957. There is some debate about the exact list, but the following are clearly identified
Abstraction
Activity
Communication
Exactness
Exploration
Manipulation (of the environment)
Order
Orientation
Repetition
Self-Perfection
Work (also described as "purposeful activity")
In the Montessori approach, these human tendencies are seen as driving behavior in every stage of development, and education should respond to and facilitate their expression. Montessori's education method called for free activity within a "prepared environment", meaning an educational environment tailored to basic human characteristics, to the specific characteristics of children at different ages, and to the individual personalities of each child.[7] The function of the environment is to help and allow the child to develop independence in all areas according to his or her inner psychological directives. In addition to offering access to the Montessori materials appropriate to the age of the children, the environment should exhibit the following characteristics:[8]
An arrangement that facilitates movement and activity
Beauty and harmony, cleanliness of environment
Construction in proportion to the child and her/his needs
Limitation of materials, so that only material that supports the child's development is included
Order
Nature in the classroom and outside of the classroom
