I don't understand where did this perspective come from? Is it from movies? I've been in this field for 6 years now, and I never encountered the stereotypical nerd in this field whatsoever. Not during my CS course not during my career.
It's a half-true stereotype. I work with people who basically do almost nothing but code or talk about code... and they're in their late 20s and 30s. I've been on dates with software engineers who bring tech stuff to the conversation a little too often for my tastes as well.
Young teens are more obsessive about hobbies so if you're really into computers at that age, that's all you do.
In the real world though, for every person like that, there's ~10 who either don't think about code after 5pm or aren't nearly as obsessive. But it's definitely a thing in our industry!
I used to be like this then my interest broaden a lot when I was about 22. I basically have friends now that I only talk via chat or when I want to talk tech since my old crowd would just chat about it perpetually.
The nerd stereotype is part of it. But there's also a part that runs along the lines of "Why would you go into CS if you haven't been fooling around with computers a whole lot in high school? Because that's what all your classmates will have been doing."
There's probably at least some analog to majoring in music. Sure, you'll probably spend a lot of your time in college learning about musical history and theory but it would probably seem a bit odd--and you'd probably be at a significant disadvantage--if you'd never had any music lessons or otherwise learned anything about music.
" seem to be able to spend their entire day focusing on a computer screen, even on weekends."
I absolutely can and have done that. Many times. In fact, it used to be most of the time.
But I'll admit that the majority of the programmers (or other IT, for that matter) I've worked with didn't seem like people who went home and played on the computer all night and all weekend.
