Adriano Pianesi argues that criticism can stimulate, rather than hinder creativity. He cites the research that debunks the "no criticism" mantra of brainstorming.
Those studies suggest that the ineffectiveness of brainstorming is due to the very thing that Osborn thought was most important. Is imagination inhibited by the merest hint of criticism? Apparently it can thrive on conflict! According to number of studies, dissent stimulates new ideas because it encourages us to engage more fully with the work of others and to reassess our viewpoints.This is the pretty much the same conclusion that Jonah Lehrer's book, Imagine, reaches. Personally, I find that a good natured enquiry into what's uncomfortable here, what's not working, can lead to much more exciting conversations than donning a plastic mask of looking on the bright side.
Hat tip: Tweet from David Gurteen