Logographeme and radical effects in reading Chinese pseudo-characters : event-related potential study

Abstract

Evidence from writing errors patterns of Chinese dysgraphic patients has advocated for the existence of the logographeme, a representational unit lying between the stroke and radical level in character processing (e.g. Law & Leung, 2000). To investigate whether logographemes qualitatively differ from radical representations, this study simultaneously examined radical independence (independent vs non-independent) and logographeme independence (independent vs non-independent) during pseudo character recognition in a lexical decision task with thirty six native Cantonese participants. A radical or a logographeme is defined as independent if it is an existing real character. Behavioral data revealed strong radical and logographeme independence effects, in which non-independent radicals or independent logographemes yielded higher accuracy and shorter latency than independent radicals or non-independent logographemes. In event-related potential (ERP) results, smaller right hemisphere positivity at the P100 and greater negativity at the N170 components were found for independent radicals, whereas greater right hemisphere negativity at the N170 component was identified for non-independent logographemes. No effects were observed at the later P200 or N400 components. The findings suggest that logographeme representational units are extracted during lexical processing, and that radicals impact on pseudo character recognition at an earlier stage of visual-orthographic processing than logographeme independence.