Jean Piaget
1896–1980 · SwitzerlandSensorimotor stage
Psychologist who mapped infant cognition from reflex to symbolic thought.
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".
Infant science bridges paediatrics, psychology, and public health.
Key figures translated observation and trial data into frameworks parents and clinicians still use.
Eight guides worth knowing
Mary Ainsworth
1913–1999 · USAttachment types
Identified secure, avoidant, ambivalent, and disorganized infant attachment patterns.
Diana Baumrind
1927–2018 · USParenting styles
Though studied older children, her authoritative framework influenced infant guidance discourse.
T. Berry Brazelton
1918–2018 · USNeonatal assessment
Neonatal Behavioral Assessment Scale clinician who taught reading infant cues.
Penelope Leach
b. 1937 · UKInfant development
Your Baby & Child linked research to practical month-by-month guidance.
William Sears
b. 1939 · USAttachment parenting
Pediatrician who coined AP acronym — babywearing, co-sleeping, breastfeeding emphasis.
Gwen Dewar
b. 1960s · USParenting Science
Anthropologist who evidence-reviewed infant sleep and cognition for public site.
WHO Nutrition
1948– · GlobalComplementary feeding
Sets global standards on exclusive breastfeeding duration and infant nutrition.
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Select up to three guides to compare side by side.
Jean Piaget
1896–1980 · SwitzerlandSensorimotor stage
Psychologist who mapped infant cognition from reflex to symbolic thought.
Mary Ainsworth
1913–1999 · USAttachment types
Identified secure, avoidant, ambivalent, and disorganized infant attachment patterns.
Diana Baumrind
1927–2018 · USParenting styles
Though studied older children, her authoritative framework influenced infant guidance discourse.
T. Berry Brazelton
1918–2018 · USNeonatal assessment
Neonatal Behavioral Assessment Scale clinician who taught reading infant cues.
Penelope Leach
b. 1937 · UKInfant development
Your Baby & Child linked research to practical month-by-month guidance.
William Sears
b. 1939 · USAttachment parenting
Pediatrician who coined AP acronym — babywearing, co-sleeping, breastfeeding emphasis.
Gwen Dewar
b. 1960s · USParenting Science
Anthropologist who evidence-reviewed infant sleep and cognition for public site.
WHO Nutrition
1948– · GlobalComplementary feeding
Sets global standards on exclusive breastfeeding duration and infant nutrition.
Pick guides above to compare.
Together they shifted infant care from schedule-driven behaviourism toward relationship-centred developmental support.
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