Laughing by yourself?

[gatorch0mp]

There's involuntary laughter and voluntary laughter... I don't think there should be much argument that location shouldn't really matter in regards to an involuntary laughing response. The voluntary laughing case (while alone) is slightly interesting. Psychologically, I can think of maybe a couple reasons to do this; (1) you want someone to hear you so they may eventually join you or (2) you're completely alone and the audible sounds of your own laughter make you feel less alone.