Physical & Cognitive Development of Adolescents

Fact Checked

iStockbyte/Stockbyte/Getty Images

Adolescence is a time of dramatic physical and cognitive development. During the middle school, high school and early college years, individuals develop from children to young adults. Their bodies mature sexually and their minds acquire the ability to engage in increasingly complex thinking, including speculative thought, intense introspection and metacognition--thinking about thought itself. These changes present major challenges and opportunities for adolescents as they develop into young men and women.

Physical Development

Girls enter the major physical changes of adolescence earlier than boys. According to the U.S. Department of Health and Human Services, girls experience a growth spurt between the ages of 9.5 and 14.5, whereas in boys the growth spurt occurs between 10-11 and 16-18. Girls can begin to develop breasts as early as age 8 and have fully developed breasts between the ages of 12 and 18. In boys, the testicles and penis may begin to enlarge as early as age 9, and genitals are typically adult-sized by the age of 16 or 17. A girl’s menarche, her first period, may begin as early as age 10 or as late as 15, with an average age of onset of 12.5. Wet dreams, which mark the beginning of puberty for boys, begin between the ages of 13 and 17.

Implications of Physical Changes

The physical changes of adolescence have a dramatic impact on the individual’s psychological and social development. As the Department of Health and Human Services notes, adolescents must deal with the embarrassment and awkwardness of disproportionate body parts. In addition, they must makes sense of their emerging sexuality, incorporate it into their sense of who they are in the world and begin to engage in intimate relationships.

Cognitive Development: Abstract Thinking

During adolescence, young people develop the ability to engage in abstract thinking. Jean Piaget, a Swiss developmental psychologist, hypothesized that it is in adolescence that humans achieve the fourth and final stage of cognitive development: formal operational thought. As explained by Grace J. Craig, the author of a textbook on human development, “This new form of intellectual processing is abstract, speculative, and independent of the immediate environment and circumstances. It involves thinking about possibilities as well as comparing reality with things that might or might not be.” This development helps to explain why many teenagers become readers of science fiction and fantasy, and develop an interest in the occult.

Implications of Abstract Thinking

There are many implications of this major step in cognitive ability. As adolescents develop the ability to compare what is to what could be, they often become critical of their parents and social institutions. They become conscious of political issues and social injustice. Ironically, at the same time, their ability to analyze their own thoughts leads to a highly egocentric worldview. As Craig explains, “Adolescents assume that other people are as fascinated with them as they are with themselves. They may fail to distinguish between their own concerns and those of others.” They develop what American child psychologist David Elkind calls an “imaginary audience”--they begin to imagine that others are constantly watching and judging them, which produces a high level of self-consciousness.

The Personal Fable

The self-absorption of adolescents leads them to develop what Elkind described as a “personal fable.” As Craig explains it, the personal fable is “the feeling that they are so special that they should be exempt from the ordinary laws of nature, that nothing bad can happen to them, and they will live forever.” As the Department of Health and Human Services points out, this way of thinking may lead teenagers to engage in risky behaviors, such as having unprotected sex, drinking and driving or chewing tobacco.