Six developmental stages. Open any one for history, science, practice and the rest.
The stage atlas
Milestone rail
Stage profiles
Newborn
0–28 days
Infant
1–12 months
Toddler
1–3 years
Preschool
3–5 years
School Age
6–12 years
Teenager
13–18 years
Open a stage
Newborn
The first 28 days after birth — physiology, bonding, feeding rhythms, and the shift from womb to world.
Evidence 88 🍼Infant
From one month to twelve months — motor milestones, first foods, attachment deepening, and emerging sleep patterns.
Evidence 90 🧸Toddler
Walking, talking, and testing limits — the toddler years blend motor explosion, language bursts, and autonomy struggles.
Evidence 85 ✏️Preschool
Imaginative play, peer entry, and executive function growth define the preschool years before formal schooling.
Evidence 82 📚School Age
Industry, friendships, and academic skill-building mark middle childhood between toddler chaos and adolescent identity work.
Evidence 78 🧑🎓Teenager
Brain remodeling, identity formation, and increasing autonomy define adolescence — risk and capability both rise.
Evidence 80