How does learning experience modulate expertise markers in the visual and auditory domains

In this thesis, I aim to examine how learning to read in different scripts modulates the way visual and spoken words are processed. In visual word processing (Chapter 2), I focused on two expertise markers for Chinese character recognition, reduced holistic processing (HP) and left-side bias (LSB) effects, and used simplified and traditional Chinese scripts as the stimuli. I found that simplified and traditional Chinese readers demonstrated a similar level of HP when processing characters shared in the two scripts, and simplified Chinese readers were less holistic than traditional Chinese readers in perceiving simplified characters. However, the two groups did not differ in HP of traditional characters, regardless of their difference in reading and writing performances. Our image analysis showed high visual similarity between the two character scripts, with a larger variance among simplified characters. This may allow simplified Chinese readers to interpolate and generalize their reduced HP skills to process traditional characters. In addition, I found that the LSB effect could be transferred to the perception of Chinese script that the readers were unfamiliar with. However, the effect that LSB was only observed in familiar fonts (i.e., font sensitivity effect) was limited to characters with the visual complexity the readers were exposed to the most often in the script they were familiar with. This font sensitivity effect was also reflected in the ERP N1 component. These effects suggest that the LSB effect may be generalized to another visual category with similar overall structures; in contrast, effects of within-category variations may depend on familiarity with featural information of the stimuli. In spoken word processing (Chapter 3), I adopted the composite paradigm used in vision research to examine HP in speech perception in logographic and alphabetic languages. I found that in processing syllables of Cantonese, which has a logographic writing system, native Cantonese speakers’ perception of syllable parts was more strongly affected by their neighboring segments than novices (native English speakers), suggesting that HP is an expertise marker for Cantonese syllable processing. In contrast, in processing syllables of Korean, which has an alphabetic writing system, native Korean speakers were less holistic than novices (including both native Cantonese and English/European language speakers), and among novices, English/European language speakers were less holistic than Cantonese speakers. These results suggest that experience with an alphabetic language may promote analytic processing, which may in turn be transferred to the auditory processing of a novel alphabetic language. To sum up, in visual perception, the results from Chinese character recognition expertise suggest that transfer of expertise effects may depend on the similarities in both overall structure and featural information between the two categories, and the variance of the categories in the mental representation space. In speech perception, the results from Cantonese and Korean syllable processing suggest that experiences with logographic and alphabetic written languages lead speakers to engage more holistic and analytic processing respectively. Taken together, the results of these studies suggest that perceptual expertise effects in both visual and auditory domains depend on learning experience.published_or_final_versionPsychologyDoctoralDoctor of Philosoph