Investigating the holistic processing of characters during Chinese reading

Background. Chinese characters are complex visual objects created from a configuration of line strokes. Little is known about the visual input required to support their recognition. However, there is longstanding debate concerning whether characters are recognized holistically, without requiring access to detailed featural information, or recognized analytically by decomposing characters into their constituent parts. Method. The present research investigated this issue using measures of eye movements during sentence reading and employing a visual blurring technique. Characters in sentences were presented as normal or with an exterior or interior region visually degraded. As the exterior region was informative about overall character shape, this manipulation allowed us to investigate effects of preserving or degrading information that might support holistic processing. Additionally, to assess effects on the lexical processing of words, each sentence included one of a pair of interchangeable two-character target words that had either a high or low frequency of written usage. Results. Our findings showed that degrading either exterior or interior character information disrupted normal eye movement behavior, suggesting that both sources of information are required to support normal reading. Effects for the two-character target words additionally showed that this disruption had additive effects on visual and lexical processing. Evidence for a processing advantage for interior degradation (which preserved holistic processing) over exterior degradation was observed in skipping rates for target words. This was consistent with readers being more likely to skip (i.e., direct their gaze beyond a word without fixating it) when holistic information about overall character shape was available. Conclusion. These results contribute to an important debate concerning the role of holistic processes in reading, by revealing that both overall character shape and detailed featural information may be required to support normal reading. However, effects in word-skipping revealed a potential role for holistic processing during parafoveal processing, during which readers attempt to recognize the next word along in a sentence. The findings showed that this proceeded most efficiently when overall character shape information was available, suggesting a role for holistic processing in parafoveal character recognition.