Phonological priming and regularity effects in reading English and Chinese

Alphabetic writing systems, like English, and logographic writing systems, like Chinese, differ in the nature of the mappings between orthography, phonology, and meaning. This thesis incorporated studies with both behavioural and neuroimaging paradigms to investigate how meaning is computed from orthographic and/or from phonological codes in reading either English or Chinese words. Three sets of homophone priming experiments using the lexical decision task are reported. The first set comprised behavioural experiments in English, where a role for sub-lexical grapheme-phoneme correspondences (GPC) is assumed. More homophone priming was obtained for targets with regular GPCs (e.g. bore-boar) than those with irregular correspondences (e.g. stake-steak) In the context of the dual-route cascaded model (Rastle & Coltheart, 1999), this regularity effect is interpreted as an interaction between the lexical route and a sub-lexical GPC-based route. In a parallel set of experiments with Chinese words and native Chinese speakers/readers, the roles of orthography and phonology were explored by varying the characteristics of phonetic radicals in primes and targets. An influence of the phonetic radical was found only when primes and targets were homophones and also shared orthographic components. Because GPC rules cannot apply in Chinese, this finding suggests an interaction of the phonetic radical and the whole character within the lexical route. These findings suggest that readers of both alphabetic and logographic scripts rely on multiple levels of orthographic and phonological information to compute word meaning; processing differences between the two languages arise mainly from constraints in the nature of the writing systems. In the third experiment, an event-related fMRI paradigm was used to explore homophone priming in English, on the rationale that priming effects in behavioural studies are typically associated with reductions in the amount of neural activation relative to unprimed task performance. A region of deactivation related to homophone priming was found in the right superior temporal gyrus (BA 38/22), which is associated with semantic relations in primed lexical decision (Rossell et al, 2001). The relative contribution of orthographic and phonological codes to the activation of word meanings is discussed.EThOS - Electronic Theses Online ServiceGBUnited Kingdo