When and how did we historically land on 18 as the age of adulthood?

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Pretty much the title. It seems 18 is universally recognized as the age of adulthood and I’m wondering why such a specific number. Why not 20 for example?

I know there are tribes around the world where children step into adulthood at a younger age, but usually there is some sort of rite of passage involved.

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12 Answers

Anonymous 0 Comments

Well in many parts of the world 18 isn’t the age of adulthood such as Cuba where it is 16.

But in the United States, the age of 18 was established as the age of adulthood through a combination of federal and state laws. In the past, the age of majority was 21, but it was gradually lowered to 18 by the passage of various laws, including the 26th Amendment to the, which granted 18-year-olds the right to vote.

Anonymous 0 Comments

I don’t know that 18 is the historical age of adulthood.

In Ancient Rome, men weren’t considered full adults until 25. In Jewish law, a boy is an adult at 13 (12 for girls). In feudal Europe and the medieval era, the age of majority for men was 21 and for married women it was 14 (16 if they were single).

Anonymous 0 Comments

There are many contradictory situations. You can be “tried as an adult” for a premeditated murder at the age of 16, and the age of “sexual consent” is typically 16 in most states.

Anonymous 0 Comments

We? If you mean America, why not state that? There are 200-ish countries in the world – YOU arrived at 18, the rest of the planet doesn’t march in lockstep with everything you do. Sorry, but it gets tiresome answering ‘why is X the way it is’ when often barely anywhere else is the same.

Anonymous 0 Comments

Your height [stabilizes](https://www.researchgate.net/profile/Stephen-Cooper-7/publication/7273759/figure/fig1/AS:202536305860608@1425299826067/Human-growth-as-a-function-of-age-This-chart-developed-by-the-Center-of-Human-Health_W640.jpg) around 18 years.

Anonymous 0 Comments

No one did. Society as a whole made that decision.

In past times, adulthood was often when puberty is completed. That’s why arranged marriages often occurred when the woman was 12-15. Males finish puberty later, often around 16. If you could afford education, it often ended around age 12 when girls returned to the home and boys were sent to either apprenticeships or higher education.

As infant mortality rates fell in the early 20th century, parents no longer expected to lose children and birth rates decreased accordingly. With fewer children who were now expected to survive to adulthood, Western cultures began to prioritize a person’s younger years and saw more value in giving children what they wanted (often toys and candy). Over time, “childhood” became extended to include teenaged years, and the age of personal responsibility increased. Each successive generation treasured their childhoods and wanted to ensure their children got even better. Today, children are treasured and losing a child is the worst form of grief, whereas before it was just another kid from the street.

For example, in WWI, women and children were expected to pick up the jobs their fathers left behind. By WWII, children were sent into the countryside in the UK to protect them. Big difference.

After WWI, many governments regulated labour markets, including minimum age to work in factories and minimum adult and child wages. After WWII we saw the development of the welfare state, where children might receive additional benefits until the age that they are allowed by law to work and earn enough to support themselves. The increase in labour laws to protect children meant that whatever age they arbitrarily selected was the age that parents would require their children to start supporting the family or themselves. That age rose from 12 to 14, to 16, then to 18. Today it is common for an 18 year old to go to college or get a job and move out. In the past 20 years, inflation in the cost of living has prevented many young adults from moving out until even their late twenties, and we see more support from parents later in life than we ever had.

Rises in average lifespan due to modern medicine have also had an impact. If life expectancy is 35, and you get married at 18 and have children at 20, then your child would be just 15 when you die. They don’t have a choice, they have to grow up early. Today life expectancy is roughly 80 in the West, so if you work to 65 your child wouldn’t have to support their parents until they turn 45. In this case, 20 is a reasonable age to expect the child to support themselves without imposing an excessive burden on their parents.

The is also a consideration between nations that should be highlighted. Many countries actually have set the age of majority at 16 for consensual sexual contact as well as driving motor vehicles on public roads. Voting is usually 18. Purchasing alcohol or tobacco is often 18 or 19, however some countries like France do not have laws against selling alcohol to customers under a certain age. The most restrictive in this respect is the US. In the “Land of the Free”, you can drive a car, join the army and create pornography at 18, but cannot drink a beer for another 3 years.

The last topic is brain development. The brain does not fully develop the areas that understand consequences until around 21-25 years of age. This is why trying a 16 year old as an adult is problematic. It also explains teenage behavior. This is also the age when mental health issues also emerge.

The result of all of these factors means that childhood is more innocent than in the past. We now try to isolate and protect children, when in the past they would have seen prostitutes in the streets, disease and death was commonplace, and everyone drank mild alcoholic drinks because water was unsafe. As quality of life has improved so dramatically in such a short period, we now treasure children. However, the realities of society mean we cannot protect the innocence of children forever, eventually they must learn about these things in order to get their own job and income and support themselves. Today, teenagers learn about sex and drugs and alcohol from each other on their own, without learning from their parents. We have to let our kids grow up eventually, and we have settled on 18 as the age that innocence can no longer be protected, and is in fact counterproductive to the goal of self-sufficient children. We impose rules on the youngest children to protect them, such as playing with matches, until they are old enough to use matches safely.

Anonymous 0 Comments

Historically there were different ages for different things. Age of mariage was usually around 12-14 if there was one, age of vote was usually around 21-25 if people could vote, etc.

18 was common for the age men could be drafted to fight for a war. It became the main age of rights because people would say that if someone can be forced to fight for its country, they should have the right to “something”, the something being vote, alcohol, smoking, etc. Then people started seeing 18 as the normal age for everything and some countries and states started postponing some rights till 18 too.

18 is still not the absolute age of rights. Age of consent is still mostly in the 14-16 range with extreme values from 12 to 18 for example. In the US, age of legal drugs is typically 21. Age of diving is often 16. Though there are people who believe 18 should be the age for everything and push for laws to be changed. It seems many people feel the need to have only one age used for laws.

18 was historically the age to be drafted (and still is where there is a draft) because it’s typically the age at which a man stop getting taller and started getting more muscular, which was very important historically for war since combat was physically very intensive. Historically, men 18-25 were considered to be the fittest so they were typically the ones to be drafted.

Anonymous 0 Comments

Roughly the end of puberty/high school would be my thought. Suspect it’s a mixture of factors depending on location and it just happens that they coincide around that age.

You could probably dig into the origins of the legal basis for age of majority in a dozen different countries and find slight differences between each.

Anonymous 0 Comments

I wouldn’t say 18 is universal. Things range country to country. If anything people are just finished with mandatory education at 18.

Anonymous 0 Comments

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