In alphabetic writing systems (such as English), the spaces between words mark the word boundaries, and the basic unit of reading is distinguished during visual-level processing. The visual-level information of word boundaries facilitates reading. Chinese is an ideographic language whose text contains no intrinsic inter-word spaces as the marker of word boundaries. Previous studies have shown that the basic processing unit of Chinese reading is also a word. However, findings remain inconsistent regarding whether inserting spaces between words in Chinese text promotes reading performance. Researchers have proposed that there may be a trade-off between text familiarity and the facilitation effect of inter-word spaces. The purpose of Experiment 1 was to examine whether there was trade-off between text familiarity and facilitation of inter- word spaces. Before reading training, Experiment 1 was conducted that 40 native Chinese undergraduates read Chinese sentences from right to left on four text conditions. The results showed faster reading speed and shorter total reading time for the inter-word spaced text. Based on this finding, 40 native Chinese undergraduates who did not participate in the first stage read Chinese sentences from right to left on four text conditions after ten-day reading training, then, the eye tracking data of participants during Chinese reading were recorded in Experiment 1. Experiment 1 verified there was trade- off between text familiarity and inter-word spaces' facilitation in Chinese, then, the Experiment 2 examined the role of text familiarity and word frequency in vocabulary recognition. Forty students read Chinese sentences under familiar (from left to right) and unfamiliar (from right to left) texts. The target words were high frequency or low frequency. Using Eyelink 1000, the eye tracking data of 32 undergraduates during Chinese reading were recorded in Experiment 2. Second, right- to-left reading training was conducted over 10 days to improve right-to-left reading experience. Then, the eye tracking data of participants during Chinese reading were recorded in Experiment 2. The results in Experiment 1 showed that: (1) Before training, there was significant different between the total reading time and reading speed under unfamiliarity text, which were shorter reading time and faster reading speed in the inter-word spaced text. (2) After training, there was no significant difference between the total reading time and reading speed in the inter-word spaced text and unspaced text, which suggests that the facilitation effect of inter- word spaces in Chinese reading changed smaller. The results in Experiment 2 showed that: (1) The effect of text familiarity was significant. The fixated time was shorter, and the skipping rate was higher under the familiar text. (2) The main effect of word frequency was significant. Low-frequency words had longer fixation times and a higher skipping rate. (3) Right-to-left training improves reading performance from right to left. (4) The early indexes showed a significant interaction between text familiarity and word frequency. A word-frequency effect occurred under the familiar but not under the unfamiliar texts. The late indexes showed that the interaction between text familiarity and word-frequency was not significant. Results in experiment 1 suggested that there was trade-off between text familiarity and the facilitation of inter-word spaces, which supported the assumption in previous studies. In addition, results in experiment 2 showed the text familiarity may affect the early processing in vocabulary recognition. Based on the Chinese integrated reading model, the word segmentation and vocabulary recognition are unified processing. The E-Z reader model holds the opposite point. Combine the experiment 1 and experiment 2, research showed that word segmentation and vocabulary recognition may be sequential processing in Chinese reading, which provided empirical evidence for Chinese E-Z reader model rather than Chinese integrated model.
