Piaget
1896–1980 · SwitzerlandCognitive stages
Piaget shaped discourse on identity and emerging autonomy through research and public writing.
Darker cells mean a higher score for this topic on that metric.
Evidence strength80
Daily impact70
Difficulty68
Age span40
Expert consensus55
Urgency60
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Last reviewed Sources & creditsMedia creditsMethodology
Quick answers
What defines teenager?
Brain remodeling, identity formation, and increasing autonomy define adolescence — framed by identity and emerging autonomy.
Is there strong evidence on teenager?
Evidence score 80/100 reflects published cohort, RCT, and meta-analytic work — gaps remain in cross-cultural replication.
Does teenager apply at every age?
Age range 13–18 years marks peak relevance; principles may extend but intensity varies by developmental stage.
How hard is teenager in practice?
Difficulty score 68/100 captures typical caregiver load — context, support, and temperament modify real experience.
What do experts agree on?
Consensus score 55/100 — areas of agreement and live debate appear in the science section.
How urgent is attention to teenager?
Urgency 60/100 reflects time-sensitivity; some topics tolerate gradual change, others need early action.
Teenager drew researchers from psychology, paediatrics, education, and anthropology.
Eight influential figures below span theory, clinical work, and global policy.
Eight guides worth knowing
William Sears
b. 1939 · USAttachment parenting
William Sears shaped discourse on identity and emerging autonomy through research and public writing.
Penelope Leach
b. 1937 · UKPractical child development
Penelope Leach shaped discourse on identity and emerging autonomy through research and public writing.
Montessori
1870–1952 · ItalyPrepared environment
Montessori shaped discourse on identity and emerging autonomy through research and public writing.
Ellyn Satter
b. 1942 · USFeeding dynamics
Ellyn Satter shaped discourse on identity and emerging autonomy through research and public writing.
T. Berry Brazelton
1918–2018 · USInfant cues
T. Berry Brazelton shaped discourse on identity and emerging autonomy through research and public writing.
Erikson
1902–1994 · Germany/USPsychosocial stages
Erikson shaped discourse on identity and emerging autonomy through research and public writing.
Judy Dunn
b. 1940 · UKSibling relationships
Judy Dunn shaped discourse on identity and emerging autonomy through research and public writing.
Guides lab
Select up to three guides to compare side by side.
Piaget
1896–1980 · SwitzerlandCognitive stages
Piaget shaped discourse on identity and emerging autonomy through research and public writing.
William Sears
b. 1939 · USAttachment parenting
William Sears shaped discourse on identity and emerging autonomy through research and public writing.
Penelope Leach
b. 1937 · UKPractical child development
Penelope Leach shaped discourse on identity and emerging autonomy through research and public writing.
Montessori
1870–1952 · ItalyPrepared environment
Montessori shaped discourse on identity and emerging autonomy through research and public writing.
Ellyn Satter
b. 1942 · USFeeding dynamics
Ellyn Satter shaped discourse on identity and emerging autonomy through research and public writing.
T. Berry Brazelton
1918–2018 · USInfant cues
T. Berry Brazelton shaped discourse on identity and emerging autonomy through research and public writing.
Erikson
1902–1994 · Germany/USPsychosocial stages
Erikson shaped discourse on identity and emerging autonomy through research and public writing.
Judy Dunn
b. 1940 · UKSibling relationships
Judy Dunn shaped discourse on identity and emerging autonomy through research and public writing.
Pick guides above to compare.
Together they moved teenager from opinion columns toward evidence-informed frameworks still debated today.
Keep exploring
Nearby ages & themes
👶
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