A comparison of hyponym and synonym decisions

Is class inclusion (hyponymy) a more primitive or simpler semantic relation than synonymy? This question was addressed by comparing the time required to identify examples of the two relations in a semantic decision task. In two experiments subjects made truelfalse decisions about statements of the form "An A is a B." In Experiment 1 category-member and synonym pairs were randomly intermixed; there was no difference between the two relations. In Experiment 2 one group was presented with the two relations randomly intermixed, as in Experiment 1 (mixed condition), while two other groups were each presented with just one of the relations (separate condition). In the separate condition responses were faster to class inclusion than to synonym pairs, while in the mixed condition there was no difference, as in Experiment 1. The results suggest that class inclusion may be a simpler relation than synonymity, although the difference may simply reflect the use to which the two relations are put in common use. The fact that the difference occurred in the separate but not in the mixed conditions suggests that the latencies reflected the evaluation of the relations against a decision criterion rather than directly reflecting lexical organization or everyday usage.