The relatedness-of-meaning effect for ambiguous words in lexical-decision tasks: when does relatedness matter?

Effects of the number of meanings (NOM) and the relatedness of those meanings (ROM) were examined for Japanese Katakana words using a lexical-decision task. In Experiment 1, only a NOM advantage was observed. In Experiment 2, the same Katakana words produced a ROM advantage when Kanji words and nonwords were added. Because the Kanji nonwords consisted of unrelated characters whereas the Kanji words consisted of related characters, participants may have used the relatedness of activated meanings as a cue in making lexical decisions in this experiment, artificially creating a ROM advantage for Katakana words. Consistent with this explanation, no ROM effect for Katakana words was observed in Experiment 3 when the Kanji nonwords consisted of characters with similar (i.e., related) meanings. These results pose a further challenge to the position that the speed of semantic coding is modulated by ROM for ambiguous words.