Never had this problem - my phone is always in silent mode. I just hate it buzzing and vibrating.

Keeping an object of addiction in front of an addict and telling him/her not to touch it causes a lot of unnecessary fixation on the object, which is why it is recommended people keep things they try to give up away. So I am not surprised the presence of their favorite smartphone made people less capable to focus on other things. This is really not new, but this study helps make smartphone addiction a thing) I hope we don't go diagnosing people with it because I swear there will be a pharmaceutical company selling another psychoactive drug to us.