Planes = think of a flat surface - a plateau on which the child can move around freely - there is a lot of back and forth and all around. The child can be far ahead on one area and not so far in something else and still not *be* behind. By the time the child is done with this plane, all areas should be on par.
Once the child reaches the next age bracket, the plane is passed - whether completed or not. If the child has had a full experience, the plane was complete and there is a strong foundation for the next. Otherwise, remediation in the next plane helps, but the same activities will NOT produce the same result. (more in another Montessori Nugget).
The theory papers on the 4 planes of development are *long*. Read The Secret of Childhood (oldest edition you can get) for more details.
1st Plane: 0-6 - Absorbent Mind - learning like a sponge - greatest growth - seeking place in family
- 0-3: infancy/toddler (physical growth and language acquisition)
- 3-6: primary (academic skills)
- Physical and Biological Independence
2nd Plane: 6-12 - Stability - quiet growth; strong on mental growth and *imagination*
- 6-9: introduction to a wide variety of concepts and cosmic education
- 9-12: consolidation of 6-9 and deeper independent studies
- Mental Independence
3rd Plane: 12-18 - Seeking place in Society - Vocation - Like a repeat of the first plane
- 12-15: Puberty - limited mental growth, focus on physical growth and changes; needs to belong
- 15-18: Reaching out into the world; abstract thinker; can handle typical high school courses with a focus on vocation, preparation for life
- Social Independence
4th Plane: 18-24 - Full member of society
Sub-planes are less noticeable - but still present
Full adult brain is developed around age 24, including the area of the brain responsible for understanding consequences prior to making a decision (unless there were severe impairments in the previous planes, when this area may never fully develop)
- Spiritual and Moral Independence
Look at your childhood - observe those around you. Do you see what is described above?