At what age does an infant typically begin to develop separation anxiety from primary caregivers?

Separation anxiety is a normal developmental milestone reflecting cognitive development. Around 6-8 months, infants develop 'object permanence' — understanding that objects (and people) continue to exist when out of sight. This enables them to miss caregivers, leading to anxiety when separated. Separation anxiety typically peaks at 10-18 months, then gradually decreases as children develop trust that caregivers return. Stranger anxiety also emerges around 6-8 months. Nursing implications: (1) Hospitalization is particularly distressing for infants 6 months to 3 years — separation from parents, unfamiliar environment; (2) Encourage parents to stay with hospitalized infants and toddlers when possible; (3) Maintain comfort items (favorite blanket, stuffed animal); (4) Routines and consistent caregivers help; (5) Goodbye rituals and reassurance about return; (6) Brief separations (parent stepping out) help develop trust that caregivers return. Excessive separation anxiety beyond developmental norms or in older children may indicate separation anxiety disorder. Other infant developmental milestones: smiles socially (2 months), holds head up (3 months), rolls over (4 months), sits without support (6 months), crawls (8-10 months), pulls to stand (9-12 months), first steps (around 12 months), first words (around 12 months).