Development Timeline

Timeline for Montessori's Planes of Development and Sensitive Periods, Erikson's Stages of (Social) Development, and Physical Movement Development. Created by Hailey Mowen for the Montessori Foundations Class

Planes of Development

1st Plane Concrete

0 AD - 06 AD

Adult’s Role: Nurturer

2nd Plane Cosmic

06 AD - 12 AD

Moral development
Social Conscience
Adult’s Role: Guide/Model

3rd Plane Cultural

12 AD - 18 AD

Physical Metamorphosis
Social Justice
Abstract Reasoning
Adult’s role: Coach

4th Plane Discernment

18 AD - 24 AD

Spiritual Maturation
Adult’s Role: Mentor

Social Development (Erikson)

Trust vs. Mistrust

0 AD - Approx. 2 AD

0-18 months
Can I Trust the World?

Autonomy vs. Shame

1 AD - Approx. 3 AD

Ages: 1-3
Is It Okay To Be Me?

Initiative vs. Guilt

3 AD - Approx. 6 AD

Ages: 3-6
Is It Okay For Me To Do, Move and Act?

Industry vs. Inferiority

6 AD - Approx. 12 AD

Ages: 6-12
Can I Make It In The World Of People And Things?

Identity vs. Role Confusion

Approx. 12 AD - Approx. 19 AD

Ages: 13-19
Who Am I? What Can I Be?

Intimacy vs. Isolation

Approx. 19 AD - Approx. 39 AD

Ages: 20-39
Can I Love?

Sensitive Periods

(The Ability to Learn is Greatest)


0 AD - 5 AD

Babbling (6-8 mo)
Words (9-18 mo)
Words to phrases (18-24 mo)
Phrases to sentences (24-30 mo)


0 AD - 5 AD

Learning to orient, walk, etc…
Ability with Small Objects 1½-3 pincer grasp, attention to detail, hand eye coordination


2 AD - 3 AD

External to internal, importance of routine

Grace & Courtesy

3 AD - 5 AD

Reverence for life, Wonder leads to empathy

Refinement of the senses

3 AD - 5 AD

Senses like sight, sound, smell, touch, taste, kinesthetic (muscular), stereognostic (touch/heat), thermic (heat), baric (weight)…are refined


4 AD - 5 AD

Moving/fitting in space
Exploration of size/shape
Exploration of cause/effect
Understanding of spoken adj./prepositions
Transition from 2D-3D (girls may have difficulty)

Similar to Sensitive Periods

6 AD - 12 AD

Sensitive periods are not quite the same because of the change in grain chemistry but some things that may occur are sensitivity to:
Imagination (foundation for abstraction)
Social Relations
Moral Development

Physical Movement

Ages: 0 - 6

0 AD - 6 AD

-Rapid growth of cerebellum
-Completion of nervous system
-Skeletal system
-Develops prehensile ability
-Development of equilibrium

Ages: 6 - 12

6 AD - 12 AD

-Loses baby fat
-New set of teeth
-Robust – less sickness
-Mortality rate is lower

Ages: 12 - 18

12 AD - 18 AD

-Puberty 12-15
-Adolescence 15-18
-Rapid physical and mental transformation
-Delicacy in the emotional and physical life

Ages: 18 - 24

18 AD - 24 AD

-Norm of the species
-Healthy and strong individual