Pre-1950
Behaviourism era
Watson and Skinner-influenced advice emphasised strict schedules and minimal picking-up.
Milestones in order. This is history, not a weekly activity grid.
- Piaget stages
- Spock bestseller
- Strange Situation
- Liedloff Continuum
- Back to Sleep prep
- WHO exclusive BF
- Three-stratum model
- AAP solids update
- COVID isolation
- Allergen introduction
Darker cells mean a higher score for this topic on that metric.
Evidence strength90
Daily impact96
Difficulty78
Age span25
Expert consensus85
Urgency80
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Last reviewed Sources & creditsMedia creditsMethodology
Quick answers
When do infants roll over?
Many roll front-to-back between 4–6 months; wide normal range exists — tummy time supports development.
When start solid foods?
WHO and AAP recommend around six months when sitting with support and showing interest — not before four months.
Is teething causing fever?
Mild drooling and gum irritation yes; high fever usually has another cause and needs medical review.
When can infants sleep through the night?
Some sleep longer stretches by 6–9 months; many still wake for feeds or comfort — biologically normal.
How important is tummy time?
Daily supervised tummy time builds neck and shoulder strength for crawling and reduces flat head spots.
When stranger anxiety?
Often peaks 8–10 months as attachment to primary caregivers solidifies — not shyness to "fix".
Infanthood became a distinct developmental stage as child psychology separated from generic "childhood" in the twentieth century.
From behaviourism's scheduled feeding to attachment parenting, advice oscillated between clock and cue.
Where it began
1960sGeneva / US labs
Jean Piaget's sensorimotor observations and Mary Ainsworth's Strange Situation (1978) defined infant cognition and attachment as measurable science.
Timeline
1934Piaget stages
Jean Piaget published sensorimotor descriptions of infant object permanence development.
1946Spock bestseller
Benjamin Spock's Common Sense Book of Baby and Child Care reached millions of US parents.
1969Strange Situation
Mary Ainsworth published attachment classification procedure at Johns Hopkins.
1975Liedloff Continuum
The Continuum Concept popularised constant carrying among Western readers.
1985Back to Sleep prep
SIDS research began linking prone sleeping to higher infant mortality.
2001WHO exclusive BF
WHO recommended six months exclusive breastfeeding where possible.
2010Three-stratum model
Gwen Dewar synthesised evidence-based infant sleep and development for parents online.
2016AAP solids update
American Academy of Pediatrics aligned complementary feeding start near six months.
2020COVID isolation
Infant social exposure limited during lockdowns — later studies tracked communication milestones.
2024Allergen introduction
Guidelines shifted toward early peanut/egg introduction after LEAP trial replication discussions.
The eras
1950–1980
Attachment revolution
Bowlby-Ainsworth work and Spock's trust-your-instincts message reshaped middle-class infant care.
1980–2000
Consumer baby boom
Baby Einstein, monitors, and gear markets exploded alongside dual-income households.
2000–2015
Evidence parenting
Websites and books translated developmental research for sleep, feeding, and play.
2015–present
Milestone anxiety
Social media and tracking apps intensified comparison culture around infant development.
Practices that changed
Approaches that faded, flipped or were replaced as evidence and culture moved on.
Scheduled feeding
1920s–1960sFour-hour bottle intervals abandoned as lactation physiology and attachment data favoured responsiveness.
Early solids
1950s–2000sRice cereal at weeks old gave way to six-month WHO-aligned introduction with texture progression.
Prone sleep
1970s–1990sProne positioning for reflux reversed after SIDS campaigns proved supine safer population-wide.
Modern infant care integrates developmental milestones as guides — not deadlines — with safety regulation on sleep and nutrition.
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 🧸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