Infant in 1934: Piaget stages 뿯½ Piaget stages

Many roll front-to-back between 4–6 months; wide normal range exists — tummy time supports development. WHO and AAP recommend around six months when sitting with support and showing interest — not before four months. 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. Daily supervised tummy time builds neck and shoulder strength for crawling and reduces flat head spots. Often peaks 8–10 months as attachment to primary caregivers solidifies — not shyness to "fix".

AAP discourages infant walkers due to fall and stair injury risk; stationary activity centres are safer. A few words or consistent gestures are typical; range is wide and bilingual infants may later on both languages. Infanthood became a distinct developmental stage as child psychology separated from generic "childhood" in the twentieth century.