Groupwork in action...?

So a couple of days ago I commented on the idea of peer instruction, and noted how it said that peer explanation worked because a student who had just learned something recently was often able to explain it to a peer.  I compared this with my rant against groupwork from a year or so ago.

I found myself feeling more open to groupwork, now that I had a context, and when I found myself in a room with fewer computers than I expected and an internet-based lesson plan, I needed to test my confidence in it.

And yes, the first group seemed to get something out of it.  One of the students with the best English was sitting with one of the guys with a pretty basic level, and he was bringing him up.  Most of the pairs were working cooperatively and discovering stuff.  Success!... I thought.

The second group weren't as good.  Every pair seemed to have one person working and the other doing nothing.  Or one person checking their email, or playing a game, or browsing the net.

But I can't say that this was due to the "groupwork" thing, because there was a rather major difference between the two groups: most of the second group bring a laptop with them, and so they weren't working on the uni desktop machines.  Was it the seating arrangements, the screen size or maybe the lack of mice (everyone was using the touchpad) that made the whole thing seem more "solo" to them?  Or was it simply that "my laptop" is "my territory"?

This is the group I'm most likely to experiment with in terms of teamwork, though, as they seem to be a fairly tight group and work on lots of activities together in other classes.  It will be interesting to challenge my own preconceptions.