[tekalon]

I can guess that your grandmother is grabbing her phone since it is the best way she can communicate with her older friends (which may or may not be home bound or far away).

I don't think it so much as being anti-social, but a more visual way of people showing that they have higher social priorities than the current situation. If they really enjoyed the conversation/activity/ or even the people they are with, they would ignore the phone.

While I'm not addicted to my phone (I often leave it at home ) I do use it on occasion as a way to 'escape' social situations that are not interesting. Dull conversation, lack of activity, or a situation where I've been dragged into some social obligation. Would do the same thing with books before cell phones.