INTERESTING: As soon as the pizza was in the process of being ordered, people got up and moved around. It went from one discussion with everyone seated around the table to several discussions with people seated/standing in a more chaotic and casual seeming manner.

I'm not sure what the topic of discussion was in the other groups was, but my conversation at the time started with nutrition and then gradually moved back to rationality related stuff. Maybe people saw it as "oh, well we're talking a break from 'rationality talk' to socialize".