Secure base
Infants use caregivers as secure base for exploration; sensitivity predicts classification in Strange Situation.
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 research combines developmental psychology, nutrition, immunology, and sleep medicine.
Longitudinal cohorts and RCTs on feeding, sleep, and screen exposure inform guidelines with varying strength of evidence.
Landmark findings
Early temperament
Thomas & Chess identified "goodness of fit" between infant temperament and parenting style.
Exclusive BF duration
PROBIT trial in Belarus linked longer exclusive breastfeeding with reduced GI infection in infancy.
Early allergens
Early peanut introduction reduced allergy incidence in high-risk infants in landmark RCT.
Screen exposure
AAP and WHO caution against passive screen time before 18–24 months due to language development concerns.
Sleep location
Room-sharing without bed-sharing associated with lower SIDS risk in first six months in case-control studies.
How it works
Synaptic pruning
Infant brain overproduces connections then prunes based on experience — enrichment and stress both sculpt circuits.
Object permanence
Memory for hidden objects emerges ~8–12 months, enabling separation games and first separation anxiety.
Gut–brain axis
Complementary feeding and microbiome shifts influence immune tolerance and possibly mood regulation.
Sleep cycle maturation
Longer REM proportions gradually shift toward adult-like architecture through the first year.
Where the evidence is strongest
Back sleeping SIDS38
Breastfeeding infection52
Early peanut allergy67
Tummy time motor81
Responsive feeding94
Back sleeping SIDS
Population campaigns linking supine sleep to lower SIDS rates show large effect sizes where compliance high.
Breastfeeding infection
Exclusive breastfeeding correlates with fewer diarrhoeal and respiratory infections in infancy across settings.
Early peanut allergy
LEAP trial showed ~81% relative reduction in peanut allergy with early introduction in high-risk cohort.
Tummy time motor
Systematic reviews link supervised prone play with earlier rolling and crawling milestones on average.
Responsive feeding
Trust-model feeding associated with healthier weight trajectories versus pressuring or restricting intake in studies.
Open debates
Sleep training age
Some paediatricians approve gentle methods from 4–6 months; others urge no intervention until older — evidence mixed on long-term harm.
BLW vs purées
Baby-led weaning advocates cite autonomy; choking concerns keep many clinicians recommending modified textures either way.
Daycare and attachment
Quality centre care can support secure attachment but low ratios and turnover remain policy debates globally.
Responsive caregiving, safe sleep, timely vaccination, and age-appropriate nutrition cover the highest-impact infant evidence base.
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