CONDITIONAL REASONING

Several techniques have been developed to examine how people understand conditional sentences. However, these techniques have produced different conclusions about if ... then. The present experiments examined two of them, the Conditional Evaluation task and the Conditional Syllogism task, to determine the cause of these differences. In Experiment 1, we collected Evaluation and Syllogism judgments from the same subjects and for the same sentences. The results showed more material conditional responses in the Evaluation than in the Syllogism task. Experiment 2 replicated this finding in a situation where subjects' reaction times were recorded. From these studies, we propose a quantitative model to explain the Evaluation-Syllogism difference in terms of the more complex processing requirements imposed by the Syllogism task. © 1979 Academic Press, Inc.