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.

Last full review/revision May 2006 by Eve R. Colson, MD