Infants: Typical Development

Below you will find a brief review of typical development, divided into four sections, each describing a different aspect of development.

  • The next page describes the impact of trauma on each of these aspects of development.
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Physical Development

Infancy, along with adolescence, is a time of enormous physical growth and change. The earliest relationship with caregivers lays the foundation for healthy brain development. Neurological development during this period proceeds from the most primitive to the most complex and is highly dependent on the infant-parent relationship. Infants are born with over 100 billion neurons; as development proceeds, these will be pruned and organized to function more efficiently and effectively than they do at birth. In the course of about a year, underlying brain structure and increasing muscle strength will change the disorganized, primitive movements of the newborn into the ability to roll over, sit, crawl, and sometimes even walk, if a bit unsteadily at first.


Cognitive Development

Brain development in the first year of life allows children’s cognitive capacities to undergo extraordinary growth during infancy. Receptive language–the ability to understand the spoken word–matures before the capacity for speech, which begins around the infant’s first birthday. Young infants initially communicate by smiling and crying, gradually adding gurgling and cooing to their repertoires, and begin to use different cries to signal different needs. Infants learn by exploring their environment, largely through their bodies and sensory perceptions—they chew on anything they pick up, repeatedly drop toys to the floor, and gleefully watch the novelty that pets and siblings introduce into their lives. Infants’ learning is highly dependent on the relationships with caregivers. When their environment provides stimulation that is not overwhelming, with adults who understand and respond appropriately to their signals, infants will develop a curiosity about their world that promotes cognitive development.


Social Development

The first years of life are crucial for social development. Because they are completely dependent for survival on the care of adults, it makes sense that babies are hard-wired for social interactions. Crying, smiling, and cooing, for example, all grab the attention of adults. When adults respond in an attuned way to infants’ signals, they are laying the foundation of social development. Infants with responsive, attuned caregivers develop a deeply held sense of trust that prepares them for satisfying relationships. Infants who are well loved and cared for carry into childhood a sense of optimism that makes them eager to explore the world. Based on their positive earliest relationships, they expect to be treated well by others.


Emotional Development

An infant’s emotional world centers around the relationship with the primary caregiver. When attuned adults respond to the infant’s cues with appropriate care—soothing, smiling, talking, feeding—the baby develops the secure attachment that lays the foundation for all subsequent relationships. This feedback loop between infant and caregiver helps infants develop increasingly sophisticated signals for alerting caregivers to their needs. When a caregiver responds to a particular cry with food, the infant learns to use that cry to send the message, “I’m hungry.” When babies yawn and rub their eyes and are then put down for a nap, they learn to associate those sensations with tiredness. These interactions help develop a sense of security and trust that the world is able to meet their needs.


The Impact of Trauma on Development »