Reflection and Reasoning in Moral Judgment: Two Preregistered Replications of Paxton, Ungar, and Greene (2012)

This study consists of two preregistered systematic replications of an experiment on reflection and reasoning in moral judgment by Paxton, Ungar, and Greene (2012). Czech students read a scenario involving incest between consenting adult siblings and an argument supporting the moral acceptability of the behavior. We manipulated the factors of argument strength (strong vs. weak) and the time that participants had to reflect on the argument (no time vs. 2 min). In the first replication (n = 347), neither the manipulated factors nor their interaction influenced how participants rated the moral acceptability of the incestuous behavior. The only significant predictor in the second replication (n = 717) was argument strength but with a very small effect. The effect of argument strength did not differ across groups either with or without deliberation time. Therefore, neither of the studies replicated the effect that deliberation time moderates the influence of argument strength on moral judgment, even though the samples were considerably larger than in the original study. We thus conclude that the effect of the interaction between the strength of an argument and deliberation time on moral judgment either does not exist or is moderated by certain contextual or sample characteristics.