Infancy and Toddlerhood
Physical and motor development
Birth weight doubles by about 5 months and triples by one year; length increases steadily. Reflexes such as rooting, sucking, Moro and palmar grasp are present at birth; some persist while others integrate. Motor milestones follow cephalocaudal and proximodistal order: head control, rolling, sitting, crawling, standing, walking. Toddlers refine walking, run, climb and self-feed.
Cognitive and language development
Piaget's sensorimotor stage, birth to 2 years, involves learning through senses and actions. Object permanence develops across substages; deferred imitation appears. Language moves from crying and cooing to babbling, first words or holophrases, then telegraphic speech. Receptive language precedes expressive language.
Social and emotional development
Attachment forms in stages; Bowlby's ethological theory and Ainsworth's Strange Situation identify secure, insecure-avoidant, insecure-resistant and disorganised patterns. Stranger anxiety appears around 6 to 8 months; separation anxiety later. Temperament and responsive caregiving shape trust, which Erikson called trust versus mistrust.
Worked example
An 8-month-old cries when a stranger approaches but smiles when mother returns; he also searches for a toy hidden under a cloth. Reasoning: stranger anxiety and object permanence both indicate the infant has a mental representation of the familiar caregiver and the object. The answer should link both to sensorimotor development, not label the child spoiled.
Traps
Do not treat attachment as instant at birth; do not call babbling first words; do not confuse separation anxiety with stranger anxiety; do not say walking is a reflex.