Abstract:  A central issue in written production concerns how phonological codes influence the output of orthographic codes. The obligatory phonological mediation hypothesis assumes that the retrieval of an orthographic representation was entirely dependent on the prior retrieval of phonological codes. By contrast, the orthographic autonomy hypothesis assumes that individuals can gain access to orthographic representation directly from meaning without phonological mediation. In a picture names writing task, we used the event-related potential (ERP) technique to examine the time course of the word frequency facilitation effect and the syllable frequency facilitation effect in Chinese handwritten production in the old. Twenty-two participants (10 males, age range: 64~81 years) participated in this study. Sixty black and white line drawings with monosyllabic words were chosen as stimuli. The experimental design included word frequency of picture names (high vs. low) and syllable frequency of picture names (high vs. low) as within-participants and between-items variables. During the experiment, participants were instructed to write picture names as fast and accurately as possible. Behavioral data indicated the facilitation effects of word frequency and syllable frequency. Writing latencies were faster in picture names with high word frequency than those with low word frequency. Similarly, writing latencies were faster in picture names with high syllable frequency than those with low syllable frequency. There was no significant interaction between word frequency and syllable frequency for behavioral data. ERP data indicated that: (1) in the time window of 200~300 ms after pictures onset, we found independent word frequency effect and syllable frequency effect. The interaction between two variables was absent. (2) in the time window of 300~600 ms after pictures onset, we found the interaction between word frequency and syllable frequency, and distinct map distributions for both effects. (3) the onset latencies of word frequency and syllable frequency effects were 212 ms and 238 ms, respectively. We therefore suggest that the early word frequency effect may originate from the retrieval of orthographic information in the orthographic lexicon, while the early syllable frequency effect may originate from the retrieval of phonological information in the phonological lexicon. The syllable frequency, as a type of phonological information, influences the relatively late stage of written production. Our findings thus provide evidences for the orthography autonomy hypothesis, rather than the phonological mediation hypothesis.

Key words: written production, word frequency effect, syllable frequency effect, orthographic autonomy hypothesis, obligatory phonological mediation hypothesis