> Think about it: when was the last time that you interrupted reading a book for watching the TV or a movie?
> But how many time you've watched your phone while doing something else?
I don't think this example proves your point. For me, a book engages ~100% of my cognitive resources; a movie also engages a large amount. Therefore, those activities can't be done simultaneously with other stuff if I'm to enjoy them or benefit from them. OTOH, social media usually engages less than 50% of my brain power, so it's a perfect thing to do simultaneously with other things that barely engage my brain and otherwise would bore me out of my mind. Hence: yes, it's reasonable to watch your phone while doing something else.
For me, social media does use all available mental resources. I timed “a quick look at twitter“ once, and when I looked at the clock after what felt like 5 minuets, I found I’d spent 40 minutes absorbed in irrelevant minutae. I can’t tell you a single tweet I read in that time.
> But how many time you've watched your phone while doing something else?
I don't think this example proves your point. For me, a book engages ~100% of my cognitive resources; a movie also engages a large amount. Therefore, those activities can't be done simultaneously with other stuff if I'm to enjoy them or benefit from them. OTOH, social media usually engages less than 50% of my brain power, so it's a perfect thing to do simultaneously with other things that barely engage my brain and otherwise would bore me out of my mind. Hence: yes, it's reasonable to watch your phone while doing something else.