Ok, I am a 30 something year old so I don't fit into either demographics...
However most of the time meetings are an out of date idea's. They historically worked because we didn't have a communication infrastructure that we do today. Conference phones where limited in the number of people on the line, issues with the person not being close enough to the phone to be heard and a slew of other communication problems, and before that it was very hard to get a bunch of people work on an idea, in a timely manner.
But really for most meetings, the individual doesn't need to be fully mentally involved unless there is something important to them. It would be much easier to chat via a message system, you can see the stuff go across your screen, while you work on something else, until something important comes up you can can then review what went on and come up with an appropriate answer.
the 20 somethings who grew up with this technology knows this and get very board during these meetings, as there is a lot of stuff that isn't important to them at the time that is going on. Now that said, It is still rude to disrupt the meeting with your activities, and if you are stuck at the meeting you should show some tact, but hopefully experience will clear that up.
So, apparently are spelling and grammar (oudated idea's - SIC).