Infant/Toddler Development

Infant/toddler development refers to the physical, language/communication, cognitive, and social/emotional progression of infants, ages birth to one year, and toddlers, ages twelve months to three years. Parents, health care professionals, and teachers or day care providers use developmental milestones to measure the growth of a child compared to other children of the same age. These behaviors or skills can help adults understand if a child is developing normally. If parents notice that their child is not hitting certain developmental milestones, they can contact their child's pediatrician to determine if there are any signs of a developmental delay. However, parents should remember that each child develops at his or her own rate and may not always achieve these milestones when other children do.

Physical Development

A newborn's physical condition is often assessed immediately after birth through a test known as the Apgar score. This test—named after its developer, Dr. Virginia Apgar—is used to determine if a newborn needs immediate medical assistance by observing the baby's appearance (skin color), pulse (heart rate), grimace response (reflexes), activity (muscle tone), and respiration (breathing rate and effort). The test is given at one minute after birth and again five minutes later. A high Apgar score usually means the newborn is healthy, but a low score does not necessarily mean a baby is unhealthy—the baby may just need some immediate medical assistance in a specific area, such as breathing. At birth, a baby's weight and height are recorded. Most babies lose weight immediately after birth and then begin gaining five to six ounces every week.

During the first year of life, infants will reach several important physical milestones. They do this by using their senses, which help babies comprehend the world around them. Newborns usually have good hearing, but their vision is limited. They cannot see very far, and it takes a few years for their vision to develop to 20/40. Their senses of smell and taste are good, and most infants respond well to touch.

As they begin to explore, babies start to develop fine motor skills, which involve the use of smaller muscles in the body, and gross motor skills, which involve the use of larger muscles in the body. Fine motor skills include activities such as using the fingers to reach for and grasp a toy, while gross motor skills include using the legs, torso, and arms to balance and walk.

Over the first few months, infants begin to roll over, reach for and pick up objects, and push up on their elbows. By six months, most infants can sit without assistance, and many children can pull to stand and even crawl by nine months of age. By one year, most toddlers can stand without help, and most children can walk by themselves by eighteen months. Many toddlers will start to run, climb up and down stairs, and throw or kick a ball by age two. When a toddler reaches the age of three, he or she can usually run and climb well and stack several small blocks without help. By three, most toddlers have quadrupled their birth weight and their height is more than 50 percent (57 percent for females; 53 percent for males) of what their adult height will be.

Language/Communication Development

The acquisition and use of language during the first three years of life is an important developmental milestone. Newborns, of course, cannot speak. They use cries to communicate their needs for things, such as food, to their caregivers. As infants grow, they begin to coo and eventually will babble in an effort to mimic the sounds they hear in their environments. By nine months, babies can understand the meaning of the word "no" and can make sounds such as "baba" or "mama."

As infants become toddlers, they may begin to communicate using gestures, such as waving goodbye, and may try to repeat words they hear. By two, many toddlers can say simple sentences made up of two to four words. Language and communication skills expand during the next year, as toddlers begin to participate in conversations, name familiar objects, and follow instructions with two or three steps.

Cognitive Development

Cognitive development involves learning, thinking, memory, and problem solving. Most experts believe that there are two basic theories of cognitive development. Psychologist Jean Piaget developed the most famous of these theories that involves four stages of development. Two of these stages occur during the infant/toddler years. Piaget believed that infants explore and interact with their environments by using their senses during the sensorimotor stage. Through activities such as sucking, grasping, and moving, they begin to understand the world around them. Piaget also contended that children understand the idea of object permanence during this stage. Object permanence is the knowledge that things and people continue to exist even when a child cannot see them.

Toddlers then move into the preoperational stage, which lasts from ages two to seven. During this stage, children use symbols to broaden their understanding of the world. According to Piaget's theory, children increasingly use language to demonstrate their symbolic thinking as they grow. Their language development, which evolves from simple sentences of one or two words to complex sentences with multiple words, demonstrates the progress of their cognitive development over time. Piaget also believed that infants and toddlers add to their understanding of the world through assimilation. In assimilation, the child uses existing knowledge to respond to new information.

Russian psychologist Lev Vygotsky presented another theory about the cognitive development of young children. Vygotsky's theory emphasizes the importance of play and social interaction in gaining knowledge and developing intellectual skills. Play is an important component of Vygotsky's theory concerning proximal development. This theory represents the difference between a child's actual cognitive development level and the potential level of development the child could reach by working with a more skilled peer or an adult. Essentially, it is the difference between what a child can do on his or her own and what the child can do with support.

By age three, a child's cognitive development has often progressed to the point that he or she can manipulate toys with moving parts, complete puzzles with three or four pieces, and play pretend games that can involve people, toys, and animals.

Social/Emotional Development

Social/emotional development begins early in infancy. Babies display sadness, happiness, and anger at a young age, and they begin to change their facial expressions to register changes in their emotions around five months. During this period, infants also become attached to parents and caregivers. Around nine months, some children will experience separation anxiety, which is a feeling of nervousness when they are away from their parents or caregivers. This anxiety may continue as the infant grows into a toddler and may last for several months. Many children also become shy around strangers during this time.

As toddlers grow, so do their personalities. Many toddlers will have, and express, preferences for favorite toys and/or people. They may also throw temper tantrums, which usually involve screaming or crying, in an effort to get something they want. However, many toddlers also freely show parents, siblings, friends, and caregivers affection by giving hugs or kisses.

By the time a toddler turns three, separation anxiety has usually ended. The child can leave his or her parents or familiar caregivers without any issues. At this point, the child will likely become less self-centered and show more concern for others, such as upset friends. The child will attempt to copy adults or friends, and he or she will be capable of displaying a range of complex emotions.

Screening for Developmental Delays

Throughout infancy and toddlerhood, children have a series of "well" visits with their pediatricians. During these visits, the doctor may ask the parents a series of questions to try to identify any delays in the child's physical, language/communication, cognitive, and social/emotional development. Pediatricians will often screen children for developmental delays at nine months, eighteen months, and twenty-four or thirty months. Parents should also discuss concerns they have about their child's development with the pediatrician as soon as possible.

A pediatrician or teacher who has concerns about a child's development may recommend that the child be evaluated for a developmental delay. In many states, the agency that handles this type of evaluation for infants and toddlers is called early intervention services (EIS). After parents contact EIS, professionals in childhood development will schedule a meeting to evaluate their child. During this meeting, these professionals observe the child, ask the child to perform certain tasks, and ask the child's parents or guardians questions about the child's development and daily routine. The evaluation will help the professionals determine if the child is eligible for services to help with any developmental delays.

Following this, the professionals and parents/guardians will develop a plan that addresses the specific delays and strengths of the child to try to address the developmental delay. For children under three, this plan is known as an individualized family service plan (IFSP). This written plan includes all of the services for the child and specific goals that the child will eventually meet with the help of trained professionals. The IFSP will also explain when and where the services will be provided.

If parents have concerns about their child's development, they should get the child evaluated sooner rather than later. The Centers for Disease Control and Prevention (CDC) noted that early intervention services can improve developmental delays significantly. These types of services can help ensure that children are ready to start school when the time comes.

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