(See also Learning and Developmental Disorders.)
Between the ages of 1 and 13, children's physical, intellectual, and emotional capabilities expand tremendously. Children progress from barely tottering to running, jumping, and playing organized sports. At age 1, most children can utter only a few recognizable words. By age 10, most children can write book reports and use computers. However, the rate of intellectual, emotional, and behavioral development varies considerably from infant to infant and from child to child. Development depends in part on
Heredity: Certain patterns may run in families, such as late walking or talking.
Nutrition: Proper nutrition is essential to development.
Environment: For example, lack of sufficient mental stimulation can slow development, whereas appropriate stimulation can speed development.
Physical problems in the child: For example, deafness can slow language development.
Although a child's development is usually continuous, temporary pauses may occur in the development of a particular function, such as speech. Doctors use established milestones—the age when most children master certain skills such as walking—to determine how a child is developing compared with other children. Various skills can develop at different rates. For example, a child may walk late but speak in sentences early.
Developmental Milestones From Birth to Age 12 Months*
Developmental Milestones From Ages 18 Months to 6 Years*
Intellect is a person's capacity for understanding, thinking, and reasoning. For intellect to develop, children must receive proper nurturing in infancy and early childhood. For example, reading to children from an early age, providing intellectually stimulating experiences, and providing warm and nurturing relationships all have a major impact on their intellectual growth and development.
At the age of 2, most children understand the concept of time in broad terms. Many 2- and 3-year-old children believe that anything that happened in the past happened "yesterday," and anything that will happen in the future will happen "tomorrow." A child at this age has a vivid imagination but has difficulty distinguishing fantasy from reality. By age 4, most children have a more complicated understanding of time. They realize that the day is divided into morning, afternoon, and night. They can even appreciate the change in seasons.
From 18 months to 5 years of age, a child's vocabulary quickly expands from about 50 words to several thousand words. Children can begin to name and to actively ask about objects and events. By age 2, they begin to put two words together in short phrases, progressing to simple sentences by age 3. Pronunciation improves, with speech being half-understandable to a stranger by age 2 and fully understandable by age 4. A 4-year-old child can tell simple stories and can engage in conversation with adults or other children.
Even before 18 months of age, children can listen to and understand a story being read to them. By age 5, children are able to recite the alphabet and to recognize simple words in print. These skills are all fundamental to learning how to read simple words, phrases, and sentences. Depending on exposure to books and natural abilities, most children begin to read by age 6 or 7.
By age 7, children's intellectual capabilities become more complex. By this time, children become increasingly able to focus on more than one aspect of an event or situation at the same time. For example, school-aged children can appreciate that a tall, slender container can hold the same amount of water as a short, broad one. They can appreciate that medicine can taste bad but can make them feel better, or that their mother can be angry at them but can still love them. Children are increasingly able to understand another person's perspective and so learn the essentials of taking turns in games or conversations. In addition, school-aged children are able to follow agreed-upon rules of games. Children of this age are also increasingly able to reason using the powers of observation and multiple points of view.
Emotion and behavior are based on the child's developmental stage and temperament. Every child has an individual temperament, or mood. Some children may be cheerful and adaptable and easily develop regular routines of sleeping, waking, eating, and other daily activities. These children tend to respond positively to new situations. Other children are not very adaptable and may have great irregularities in their routine. These children tend to respond negatively to new situations. Still other children are in between these two ends of the spectrum.
Crying is an infant's primary means of communication. Infants cry because they are hungry, uncomfortable, distressed, and for many other reasons that may not be obvious. Infants cry most—typically 3 hours a day—at 6 weeks of age, usually decreasing to an hour a day by 3 months of age. Parents typically offer crying infants food, change their diaper, and look for a source of pain or discomfort. If this does not work, holding or walking with the infant sometimes helps. Occasionally nothing works. Parents should not force food on crying infants, who will readily eat if hunger is the cause of their distress.
At about 8 months of age, infants normally become more anxious about being separated from their parents. Separations at bedtime and at places like child care centers may be difficult and can be marked by temper tantrums. This behavior can last for many months. For many older children, a special blanket or stuffed animal serves at this time as a transitional object that acts as a symbol for the absent parent.
At 2 to 3 years of age, children begin to test their limits and do what they have been forbidden to do, simply to see what will happen. The frequent "nos" that children hear from parents reflect the struggle for independence at this age. Although distressing to parents and children, tantrums are normal because they help children express their frustration during a time when they cannot verbalize their feelings well. Parents can help decrease the number of tantrums by not letting their children become overtired or unduly frustrated and by knowing their children's behavior patterns and avoiding situations that are likely to induce tantrums. Rarely, temper tantrums need to be evaluated by a doctor. Some young children have particular difficulty controlling their impulses and need their parents to set stricter limits around which there can be some safety and regularity in their world.
At age 18 months to 2 years, children typically begin to establish gender identity. During the preschool years, children also acquire a notion of gender role, of what boys and girls typically do. Exploration of the genitals is expected at this age and signals that children are beginning to make a connection between gender and body image.
Between 2 and 3 years of age, children begin to play more interactively with other children. Although they may still be possessive about toys, they may begin to share and even take turns in play. Asserting ownership of toys by saying, "That is mine!" helps establish the sense of self. Although children at this age strive for independence, they still need their parents nearby for security and support. For example, they may walk away from their parents when they feel curious only to later hide behind their parents when they are fearful.
At 3 to 5 years of age, many children become interested in fantasy play and imaginary friends. Fantasy play allows children to safely act out different roles and strong feelings in acceptable ways. Fantasy play also helps children grow socially. They learn to resolve conflicts with parents or other children in ways that help them vent frustrations and maintain self-esteem. Also at this time, typical childhood fears like that of "the monster in the closet" emerge. These fears are normal.
At 7 to 12 years of age, children work through numerous issues: self-concept, the foundation for which is laid by competency in the classroom; relationships with peers, which are determined by the ability to socialize and fit in well; and family relationships, which are determined in part by the approval children gain from parents and siblings. Although many children seem to place a high value on the peer group, they still look primarily to parents for support and guidance. Siblings can serve as role models and as valuable supports and critics regarding what can and cannot be done. This period of time is very active for children, who engage in many activities and are eager to explore new activities. At this age, children are eager learners and often respond well to advice about safety, healthy lifestyles, and avoidance of high-risk behaviors.