I've noticed this, even at older ages. My early teen son turns into a downright asshole if he's online and then told (with ample warning) that it's time for dinner. Without the device, he's extremely pleasant.
I can still remember this sort of situation when I was a teenager playing CounterStrike every day. For one thing, my mom would give me "ample warning" but without checking that I was paying attention to her first. When your focus is 100% on a game it's easy to not notice and even to answer without noticing what was said to you. Basically say whatever would make her go away the fastest and then get back to the game. Then when dinner truly was ready and she interrupted me abruptly, it was frustrating because I never got (in my head) proper notification. Often I would actually not remember her giving me a heads up, it was that small a blip in my focus. She called it selective hearing.
I think those of us who spend a lot of time online/on devices project our consciousness into the machine and it takes more effort to context switch out of that. So we get angry when we're torn out without the chance to context switch at our own pace. For what it's worth, I get the same way when I'm deep into reading a book so I wouldn't project this problem on only high technology.
