Abstract

College-student subjects made notes about the morality of early abortion, as if they were preparing for a class discussion. Analysis of the quality of their arguments suggests that a distinction can be made between arguments based on well-supported warrants and those based on warrants that are easily criticised. The subjects also evaluated notes made by other, hypothetical, students preparing for the same discussion. Most subjects evaluated the set of arguments as better when the arguments were all on one side than when both sides were presented, even when the hypothetical student was on the opposite side of the issue from the evaluator. Subjects who favoured one-sidedness also tended to make one-sided arguments themselves. The results suggest that ?myside bias? is partly caused by beliefs about what makes thinking good