Continuing the discussion of polarization: One of Cass's papers on the topic discusses the development of academic "schools" (law and economics or critical legal studies, for example) as such examples of group polarization and cascades. I read the paper, maybe against Cass's intention, as offering some good reason for homogeneity at one, early, intellectual stage of development. People are more likely to see an idea through to its conclusions and to test its limits if they are receiving informational and reputational signals from those around them that the idea is a promising one. In other words, a potential intellectual school is most likely to develop into a genuine one in a somewhat homogenous environment. But the time and place for that homogeneity clearly runs out at a certain point. A major conference roundtable (at least at APSA, "roundtable" means "speeches" whereas "panel" means "the presentation of pre-circulated papers) isn't a place where research agendas are developed and explored, but one where they're propounded and proclaimed. Homogeneity in that context is more like a rally than it is like a research institute, and the group polarization that follows is likely to be boring at best, oppressive at worst, without any of the potential to generate fruitful new ideas that comes from some homogeneity at the earlier stage. I should add that I think the benefits of homogeneity at the earlier stage are temptingly easy to exaggerate. Cass' paper is careful about this. The same social settings that nurture an intellectual school of great promise, one that might have been squelched in a more heterogenous setting, can also nuture pointless fads that would have been better squelched. But if schools of thought are an important part of learning and intellectual development over time, then some dumb fads might be a price that has to be paid for them. --Jacob T. Levy