The Second Year

Physical Development

While overall rate of growth continues to decline, the toddler continues to experience considerable brain growth and myelination in the 2nd yr of life, resulting in an increase in head circumference of 2 cm over the year ( Figs. 23.1 and 23.2 ). Toddlers have relatively short legs and long torsos, with exaggerated lumbar lordosis and protruding abdomens.

Most children begin to walk independently at about 12-15 mo of age. Early walking is not associated with advanced development in other domains. Infants initially toddle with a wide-based gait, with the knees bent and the arms flexed at the elbow; the entire torso rotates with each stride; the toes may point in or out, and the feet strike the floor flat. The appearance is that of genu varum ( bowleg ). Subsequent refinement leads to greater steadiness and energy efficiency. After several months of practice, the center of gravity shifts back and the torso stabilizes, while the knees extend and the arms swing at the sides for balance. The feet are held in better alignment, and the child is able to stop, pivot, and stoop without toppling over (see Chapters 692 and 693 ).

Cognitive Development

Exploration of the environment increases in parallel with improved dexterity (reaching, grasping, releasing) and mobility. Learning follows the precepts of Piaget's sensorimotor stage (see Chapter 18 ). Toddlers manipulate objects in novel ways to create interesting effects, such as stacking blocks or filling and dumping buckets. Playthings are also more likely to be used for their intended purposes (combs for hair, cups for drinking). Imitation of parents and older siblings or other children is an important mode of learning. Make-believe play ( symbolic play ) centers on the child's own body, such as pretending to drink from an empty cup ( Table 23.1 ; see also Table 22.1 ).

Emotional Development

Infants who are approaching the developmental milestone of taking their 1st steps may be irritable. Once they start walking, their predominant mood changes markedly. Toddlers are often elated with their new ability and with the power to control the distance between themselves and their parents. Exploring toddlers orbit around their parents, moving away and then returning for a reassuring touch before moving away again. A child with secure attachment will use the parent as a secure base from which to explore independently. Proud of her or his accomplishments, the child illustrates Erikson's stage of autonomy and separation (see Chapter 18 ). The toddler who is overly controlled and discouraged from active exploration will feel doubt, shame, anger, and insecurity. All children will experience tantrums, reflecting their inability to delay gratification, suppress or displace anger, or verbally communicate their emotional states. The quality of the parent–child relationship may moderate negative behavioral effects of childcare arrangements when parents work.