After putting away childish things one became an adult - from records, many children  began as adults. Now we have teens some of  whom often need counselling  or their parents do? When did they happen?

The term was first coined in the late '30s, but the concept had evolved when a combination of child labour law, educational system developments, and a trend towards later marriage age created the need to recognise that stage of growing up as a distinct phase with its own unique characteristics, challenges and - ultimately - subculture. It didn't arise at the same time in all cultures, and in some cultures still doesn't exist, but in western society arrived with a bang in the post-war baby boom which coincided with a marked increase in spending power across the board, but in the US also among these new-fangled creatures which had suddenly presented themselves for economic exploitation.

Hormones, which are essentially just chemical messengers between cells, had hit mainstream consciousness from around the mid-30s after first being described in 1905. "Hormonal changes", a misunderstanding of how hormonal development and function actually manifests itself in the human body, had already become a common attribution for odd behaviour amongst women and adolescents in US court rooms by the 1940s. Such "evidence" wouldn't be allowed today in any self-respecting court of law run by people who have actually learned science, but we still persevere with the myth today as an explanation for excessively violent, self-centred, unreasonable and downright shitty behaviour by people who are too immature to cope with responsibility without sufficient exposure to it as a reality to be coped with, yet too mature to be distracted from such self-indulgence using methods that work for children. While they endure this vacuum within their personal development, and we endure their antics, they are "teenagers".

Looking back, I think I managed to be a "teenager" for two summers in total (it was a seasonal thing subject to weather where I came from), and even then was strictly amateurish at the game compared to my peers. I arrived late due to lethargy and had to depart early due to some rather harsh impositions from the real world, regardless of hormones.

Interesting insight there - moving on - at the Durrell Zoo in Jersey I was fascinated by a rogue pair of teen gorillas who were wrecking their environment and generally behaving badly. The  silver back  began glowering and huffing with menace but the keepers said not to worry,they had another enclose for the naughty pair when it became really necessary to cool things down. On the other hand, the nearby orangutans with a similar lively pair handled it with recognizable aplomb. An adult female found a large paper sack and put that over her head and indolently rested on a branch - the large  clan male had already sloped off to his hammock in the covered enclosure.

How is a teenage gorilla defined? A gorilla between 13 and 19 years of age has already entered full reproductive mode and, with an age span in total of between 35 and 40 years would at that stage be the equivalent of a human between their mid twenties and about 40 years old. There is no doubting that human males in particular of this age are capable of quite startlingly violent, self-indulgent and anti-social behaviour, but even those with the greatest faith in the hormone myth don't ascribe this as a cause in that case.

Gorillas in captivity behaving "badly" may in fact be exhibiting a rather intelligent and logical reaction, if tragic in its implications for the individuals, to their predicament. Unless you lock your local teenager up in his/her room and invite the neighbours round to watch them through the window every day, I'm not sure the two cases are completely comparable.

Moving on ...

I suspect the "teenager" wasn't invented, but developed as a result of not being in full-time work, so probably did not exist before the Education Act of 1899 raised the age of leaving compulsory education to 13.

Oh, I didn't know the term arose in the 1930s.  I always assumed it came into being in the 1950s although I had a work colleague who used to tell me one should never assume anything.

My grandmother, speaking in the 1950s or 60s, used to say that a teenager meant someone over the age of ten.  I don't think the term was new to her then, though her definition of it wasn't what we thought.  I still think of it as someone between the ages of 13 and 19.  (Though I might consider 18 and 19-year-olds as 'young adults'.

Caro wrote:

My grandmother, speaking in the 1950s or 60s, used to say that a teenager meant someone over the age of ten.  I don't think the term was new to her then, though her definition of it wasn't what we thought.  I still think of it as someone between the ages of 13 and 19.  (Though I might consider 18 and 19-year-olds as 'young adults'.

Caro,

to know of what I was speaking I read first the wiki about it:
https://en.wikipedia.org/wiki/Young_adult_(psychology)
My first reaction before reading the wiki, was to see the adult from the thirties on and starting the young adult from 20 on, and then teenagers up to 20...but there are big differences in behaviour...I have seen teenagers acting even as adults...and adults acting as children...
But now wiki:
I first wanted to make a summary, but as it is so complex I think you would best read it yourself.
Some example:
"Some have suggested that, after 'Pre-adulthood... in the first 20 years or so... the second era, Early Adulthood, lasts from about age 17 to 45... the adult era of greatest energy and abundance and of greatest contradiction and stress.'^[2] Within that framework, 'the Early Adult Transition (17–22) is a developmental bridge between pre-adulthood and early adulthood',^[2] recognizing that 'the transition into adulthood is not a clear-cut dividing line'.^[5] One might alternatively speak of 'a Provisional Adulthood (18–30)... [&] the initiation to First Adulthood'^[6][7] as following that."

Kind regards from Paul.