Morphemic relationships in the lexicon: are they distinct from semantic and formal relationships?

The influence of morphemic relationships on the repetition priming effect, which is presumed to provide an index of lexical organization, was examined in several experiments. An attempt was made in all experiments to minimize nonlexical contributions to these lexical effects by placing related items in a context of unrelated items. Priming among regularly and irregularly suffixed morphemic relatives, associates, and synonyms was examined. Morphemic relatives and associates yielded significant priming, although priming was largest for regularly suffixed morphemic relatives. Priming was not obtained for synonyms. In previous research (Napps & Fowler, 1987), priming was not found among orthographically and phonologically related words. The results are interpreted to mean that morphemic priming is not the result of the convergence of semantic, orthographic, and phonological relationships, but rather that morphemic relationships are represented explicitly in the lexicon.