In "The Rise of the New Groupthink" (New York Times, tiered subscription model) by Susan Cain, the author argues that for a variety of tasks, solitude is the best mode of working. Despite this, business and education press ahead with having people work in groups. The takeaway of the article is the line, "If you have talented and motivated people, they should be encouraged to work alone when creativity or efficiency is the highest priority," quoting organizational psychologist Adrian Furnham.
I'm not sure how much I agree with the article, which is basically an ad for Cain's book, Quiet: The Power of Introverts in a World that Can't Stop Talking. But it's the first time in a long time I've seriously questioned my judgment of group work as inherently superior for educational purposes than individual work. I will definitely read the book at some point.