中華心理衛生協會

Purpose: Reading fluency requires the ability to integrate orthographic, phonological, and semantic representations. While many studies have focused on the effect of vocabulary size on orthographic and phonological processes with Chinese characters, few have explored the effect of vocabulary size on semantic processing. Three cross-modal experiments of semantic relatedness judgment were conducted to address this topic. Experiment 1 evaluated the difference between 24 fifth graders and 24 adults. Experiment 2 replicated the findings in Experiment 1 through matched intelligence scores between 12 adults and 12 fifth graders. In Experiment 3, we tested the semantic judgments of 2 groups of fifth graders with different vocabulary sizes. Methods: We manipulated the semantic association between character pairs (strong, weak, and unrelated). The first character was presented visually and the second character was presented orally. Participants indicated whether the 2 characters were semantically related. Results: Reduced accuracy and longer reaction times were found for character pairs with weak associations, as compared to those with strong associations across the 3 experiments, suggesting that there are increased selection demands when processing distantly related pairs. In the first experiment, as in the second experiment with paired intelligence scores, the difference between strong and weak association strength was larger for the adults than for the fifth graders. The findings remained after partialling out working memory scores with ANCOVA analyses. In the third experiment, fifth graders with a larger vocabulary size showed better performance for both strong and weak association character pairs as compared to fifth graders with a smaller vocabulary size. The findings remained after partialling out working memory scores by ANCOVA analyses. Conclusions: Both age and vocabulary size were found to be related to semantic processing. The visual-auditory presentation required participants to select a semantically appropriate answer for the second homophonic character. This selection mechanism required searching for and integrating the overlapping semantic features of the 2 presented characters. In Experiments 1 and 2, fifth graders demonstrated poorer search and integration of semantic features as compared to adults. Adults may have more close connections in their semantic representational systems available to process strongly related pairs than weakly related pairs. In contrast, fifth graders may not be able to differentiate effectively the semantic relationship between strong and weak pairs. As age increases, children with more reading experience may have more elaborate semantic representations and thus more close semantic connections with which to process characters. Moreover, participants may need to be competent in mapping visual form, sound, and meaning between the first and the second characters in these cross modal tasks. Mapping ability between lexical representations may affect participants' performance in selecting the semantically appropriate answer. Fifth graders with a smaller vocabulary size may be deficient in mapping among semantics, phonology, and orthography, producing poorer performance on meaning judgments as compared to fifth graders with a larger vocabulary size.