That's a good distinction. I think however, in the case of phone use among schoolchildren, "smartphone" and "social media" are nearly synonymous. You just can't get a lot of the negative aspects of phone usage without tying it down to social media. (I'm thinking of your Likes, public shaming, low self esteem, distraction by notifications, photo filters, narcissism, addiction, short attention spans, difficulty concentrating, etc. It's hard(er?) to pull that off without the deep pockets of social media giants.)