Z:gnu-www-ja-frank--9023ba-Yet another concern with the M/en

Yet another concern with the Marwell and Ames experiments is not easily dismissed. Although the authors do not report the sex composition of their group of economics graduate students, such groups are almost always preponderantly male. The authors' control groups of high school and undergraduate students, by contrast, consisted equally of males and females. As our own evidence will later show, there is a sharp tendency for males to behave less cooperatively in experiments of this sort. So while the Marwell and Ames findings are suggestive, they do not clearly establish that economists behave differently.