Different Roles of Initial and Final Character Positional Probabilities on Incidental Word Learning during Chinese Reading
Abstract: In natural unspaced Chinese reading, there are no salient visual word segmentation cues (like word spaces) to demark where words begin or end, yet Chinese skilled readers process a comparable amount of text content as efficiently as English readers, processing roughly 400 characters (equal to 260 words) per minute (see Liversedge et al., 2016). This raises the question of how Chinese readers engage in such word segmentation processing efficiently and effectively. Liang et al (2015, 2017) have shown that the positional probability information associated with a character, might offer a cue to the likely positions of word boundaries during Chinese incidental word learning. Given that they simultaneously manipulated the positional probabilities of both word initial and word final characters to make their manipulations maximally effective, it is unclear whether the initial, the final, or both constituent characters' positional probabilities contribute to the word segmentation and word identification effects during incidental word learning in Chinese reading. For this reason, in the present study, two parallel experiments were designed to directly investigate whether word initial, or word ending characters are more or less important for word segmentation word learning in Chinese reading. Two-character pseudowords were constructed as novel words. Each novel word was embedded into six high-constraint contexts for readers to establish novel lexical representation. In Experiment 1, we examined how words initial character positional probability influenced word segmentation and word identification during Chinese word learning. The initial characters positional probability of target words was manipulated as being either high or low, and the final character was kept identical across the two conditions. In Experiment 2, an analogous manipulation was made for the final character of the target word to check whether the final character positional probability of two-character words can be used as word segmentation cue. We also included Exposure as a continuous variable into the model to further examine how the process of initial and final character positional probabilities changed with exposure. In both experiments, the participants spent shorter reading times and made fewer fixations on targets that comprised initial and final characters with high relative to low positional probabilities, suggesting that the positional probability of both the initial and final character of a word influences segmentation commitments in novel word learning in Chinese reading. Furthermore, both the effect of initial and final character positional probabilities of novel words decreased with exposure, showing the typical familiarity effect. To be somewhat different, the familiarity effect associated with the initial character had a slower time course relative to final character. This finding suggests that the role of words initial character positional probability is of more importance than that of final characters, supporting the concurrent standpoint that word beginning constituents might be more influential than word final constituents during two-character word identification in Chinese reading. Based on the findings above, the time course of the process of initial and final character positional probabilities of novel words is argued and summarized as follows. During the early stage of word learning, both the statistical properties of words initial and final character positional probabilities are processed as segmentation cue. As lexical familiarity increases, the extent to such segmentation roles decreases, which initially begins with final character, and then occurs with initial character. Later, both the roles of initial and final character positional probabilities disappear with the establishment of a more-integral representation of novel words.