I agree the studies are very narrow, but that's really a requirement, in a study like this you have to narrow things down very tightly to eliminate extraneous factors. I know it's hard to believe now, but these findings in the 70s really were shocking, many psychologists and philosophers thought the results were impossible. I think it's hard for people nowadays to put themselves back into that context.
On the reasoning problem, I don't think it's fair to include the people that spotted the trick in the final analysis. The fact that 60% of people that didn't know they were contradicting themselves did so perfectly happily just in order to feel consistent despite evidence to the contrary is pretty shocking.
Anyway, thanks for the discussion.