For myself, the availability of electronic devices affects my attention. I often keep my phone silent at work, it gives myself a reason to check it every hour or so. Sometimes, I open my phone to do some calculations, but it is tempting to check for some news, some tweets and I forget my initial purpose. So I turn my phone on to see if it makes a difference. Be honest, it does not help much. Even I know there are no unread emails, I still double check. Sometimes I forget my phone at home for a whole day and I see a difference. So, when I need to focus, I often leave electronic devices out of my hands.