Is there a study on this? Personally I've never felt distracted by non-participating neighbors (with the notable exception of one guy next to me who spent an 80-minute class looking for porn on Google Images), but for all I know my peers have.
I did read a study on this at some point in the past year, but my google-fu is failing me today. IIRC the results were that neighbors using laptops were distracting to surrounding students.
