Adulthood

Adulthood is the stage of human life that comes after childhood and the teenage years. It is the longest stage of life for most people. An adult is someone whose body has finished growing and who is old enough to make their own choices about work, where to live, and how to spend money. In most countries, the law treats a person as an adult starting at age 18.

The body changes a lot before adulthood begins. During puberty, kids grow taller, gain muscle or curves, and their bodies become able to have children. By the early 20s, most of these changes are finished. Bones reach their final length. Adult teeth, including the wisdom teeth at the back of the mouth, are usually all in. Most adults stop growing taller around age 18 to 20.

The brain takes longer to finish than the rest of the body. Scientists used to think the brain was fully grown by the late teens. New research, mostly from brain scans, shows that the brain keeps changing into the mid-20s. The last part to finish is the front of the brain, called the prefrontal cortex. This area helps people plan ahead, weigh risks, and stop themselves from doing something they will regret. That is one reason a 25-year-old often makes calmer choices than a 15-year-old.

Adulthood is often split into three rough parts. Young adults, from about 20 to 40, are usually at peak physical strength. Middle adulthood, from about 40 to 65, is when many people raise children and reach the top of their careers. Older adulthood begins around 65. The body slows down in middle and older adulthood. Hair turns gray. Eyesight often gets worse. Reaction times get slower.

But the news is not all about slowing down. Studies show that some skills get better with age. Adults often have larger vocabularies than younger people. They are usually better at solving social problems, handling strong emotions, and seeing the big picture. This kind of knowledge built from years of experience is sometimes called wisdom.

How long does adulthood last? Today, the average person in the United States lives to about 77 years old. A hundred years ago, the average was closer to 54. Better food, clean water, vaccines, and modern medicine added more than two decades to the average life. The longest confirmed human life belonged to a French woman named Jeanne Calment, who lived to 122 years old.