The use of analogy in legal argument: Problem similarity, precedent, and expertise

This paper reports the results of two studies which examine semantic similarity and pragmatic centrality in the use of analogy in legal reasoning. The first study investigated the effects of surface and structural similarity on the transfer of knowledge by analogy. In this experiment, 63 graduate students and 38 experienced professionals resolved a tax problem after reading and analyzing three tax cases (source analogs). In the control condition, all three analogs were unrelated to the problem. In the treatment condition one of the analogs was unrelated to the problem, one shared only surface features with the problem, and one shared only structural features. Both experts and novices exhibited high rates of transfer from the analog that shared structural features with the problem. There was negligible transfer from the analog sharing surface features with the problem. The second study examined the interaction of semantic similarity with pragmatic centrality. In this study 128 professionals and 146 students resolved a tax problem after reading and analyzing four tax cases. Pragmatic centrality was manipulated in the materials by varying the outcome of the source analogs. Prediction of the problem outcome varied with the direction of the outcome of the source analogs. Transfer from both the structural analog and the surface analog varied with the outcome of the analog, and transfer was greater in instances in which the outcome of the structural analog was consistent with the predicted outcome. This result contrasts to results of the first study when pragmatic concerns were held constant and both experts and novices relied on the structural analog and ignored the surface analog. The pattern of results in the two studies suggests that pragmatic considerations override similarity constraints in the use of analogy in an adversarial domain.