The term kid is of Middle English and Scandinavian origin and is used to refer to people who are younger, usually those who are in the developmental stage of childhood.http://www.merriam-webster.com/dictionary/kids However, adults, especially parents, often use the term “kids” to refer to their children at any age.
Child development is split into four stages: 1) Infancy, which lasts from birth to two years of age, 2) early childhood, which ranges from ages two to six, 3) middle childhood, from six to twelve, and 4) adolescence, which follows development from twelve to eighteen years of age.http://family.jrank.org/pages/239/Childhood-Stages.html Children within the stages of early and middle childhood are the most likely to be referred to as kids.
Kids in Early Childhood
Early childhood is often referred to as the “play years.” During this period of development, kids learn primarily through play.http://family.jrank.org/pages/239/Childhood-Stages.html Kids begin to interact with other children more during this stage and engage in fantasy and imaginary play activities.http://www.parentfurther.com/ages-stages/3-5
Cognitively, kids in early childhood develop more advanced thinking skills than they had in infancy. They are able to categorize concepts within the brain and also develop a “theory of mind,” the ability to understand what another person may be thinking, a stepping stone toward empathy.http://family.jrank.org/pages/239/Childhood-Stages.html Language development also increases, with the average vocabulary of a five year old consisting of approximately 2500 words, up from 300 words for most three year olds.http://www.parentfurther.com/ages-stages/3-5
Kids in Middle Childhood
Middle childhood is marked by the developmental milestone of “concrete operational” thinking. Coined by psychologist Jean Piaget, concrete operational thinking refers to the ability in middle childhood for kids to think logically but flexibly. Kids in this stage begin to understand concepts such as conservation and show more organized thought processes.http://family.jrank.org/pages/239/Childhood-Stages.html
This is also a period in which kids begin to reach out to peers outside the family and take on more of an individual identity.http://www.childdevelopmentmedia.com/middle-childhood-development.html By the ages of 8 and 9, kids can manage several peer relationships and enjoy having fun in group settings.http://www.parentfurther.com/ages-stages/6-9 The ages between 8 and 12 are sometimes referred to as the “tween” years, however, kids this age are still considered a part of the middle childhood stage.http://www.usatoday.com/news/health/2009-02-03-tweens-behavior_N.htm