Z:gnu-www-ja-frank--a41693-It was only in a twelfth repli/en

It was only in a twelfth replication with first-year graduate students in economics as subjects that Marwell and Ames obtained results more nearly consistent with the self-interest model. These subjects contributed an average of only 20 percent of their initial endowments to the public account, a figure significantly less than the corresponding figure for noneconomists (p&lt;.05).