The Explicit and Implicit Phonological Processing of Chinese Characters and Words in Taiwanese Deaf Signers

Abstract

This study investigates the phonological processing that Taiwanese deaf signers engage in when recognizing Chinese characters and words. The deaf participants\' orthography-phonology transformation (OPT) abilities were tested using an explicit Chinese homophone judgment task, and their implicit phonological activations were tested using lexical decision tasks. Chinese characters, whose phonetic radicals are not always reliable guides to pronunciation, are a useful tool for dissociating the influence of phonology and orthography. Experiment 1 manipulated sound-based phonological similarity (similar, dissimilar) and orthographical similarity (similar, dissimilar). Accuracy, sensitivity (d\'), and reaction times (RTs) were recorded for hearing participants, but only accuracy and sensitivity (d\') recorded for deaf participants, who are fluent signers of Taiwanese Sign Language (TSL). Additionally, the predictive abilities of log word frequency and the consistency values for homophone judgment performance were analyzed. Experiment 2-1 was designed to compare the effects of three primes (semantically related, sound-based phonologically related, and unrelated primes) on the performance of deaf and hearing participants on a lexical decision task. In Experiment 2-2, TSL phonologically related primes were compared with unrelated primes for deaf and hearing subjects. The results of Experiment 1 show that the accuracy of deaf subjects was poor (. 66) and was lower than that of hearing subjects (. 87). Particularly, the deaf subjects\' accuracy and sensitivity in the orthographically dissimilar condition were significantly lower than in the orthographically similar condition. For hearing subjects, log word frequency significantly predicted their accuracy and RTs, whereas the consistency values predicted only the RTs. For the deaf participants, the accuracy could be efficiently predicted by both log word frequency and consistency values, which reflect knowledge of OPT rules. We suggested that although deaf individuals had acquired knowledge of OPT rules, this knowledge was neither complete nor sufficiently robust to make homophone judgments. In Experiment 2-1, the results show that there was a semantic priming effect but no sound-based phonological priming effect for the deaf participants. The results further reveal that deaf people with a limited hearing ability did not automatically process the sound-based phonological representations under time-constrained conditions. In Experiment 2-2, there was an action-based phonological priming effect for deaf signers but not for hearing subjects, indicating that deaf signers automatically activated related action-based phonology to access the semantic meaning of words when reading Chinese. This study finds that deaf signers acquire OPT rules but that their OPT rules are not sufficiently robust or complete to allow them to make explicit phonological judgments and homophone judgments. Deaf signers automatically activated action-based representations rather than sound-based phonological representations when reading Chinese characters.