The word frequency effect of fovea and its effect on the preview effect of parafovea in Tibetan reading

In the process of reading, readers mainly obtain information through the fovea region—in particular, the parafovea plays an important role in information acquisition. Readers can obtain certain information from the parafovea through previewing processing, thus promoting the improvement of reading efficiency, which is called the “previewing effect”. The effect of the processing load of the fovea on the previewing effect of parafovea has become a popular research focus of late. For example, studies based on alphabetic languages have found that the previewing effect of the parafovea is greater for high-frequency and short words than for low-frequency and the long words. While Tibetan is an analphabetic language, it also belongs to the Sino-Tibetan language family and has many similarities with Chinese. However, it is still largely unclear how to reflect the above role in the process of Tibetan reading. Will it only show the common characters of alphabetic languages or will it show some Chinese characteristics? The present study aimed to provide experimental evidence to respond to these research questions. Two experiments were carried out on 119 Tibetan undergraduate students. More specifically, participants were asked to read Tibetan sentences and their eye movements during reading were recorded using an SR Research EyeLink 1000Plus eye tracker (sampling rate = 1000 Hz). Experiment 1 manipulated the fovea word frequency (i.e., high vs. low frequency) to investigate the word frequency effect and word frequency delay effect of fovea words in Tibetan reading. The results showed a word frequency effect and a word frequency delay effect in Tibetan reading. Experiment 2 manipulated both fovea word frequency and parafovea previewing word types with the aid of boundary paradigm to investigate the previewing effect of parafovea and the effect of fovea word frequency on the previewing effect of parafovea in Tibetan reading. The results showed a previewing effect of parafovea in Tibetan reading and that, when compared with low-frequency fovea words, high-frequency fovea words had a greater promoting effect on the previewing effect of parafovea. The primary findings can be summarized as follows: (1) significant word frequency effect exists in Tibetan reading, which is reflected in the whole process of vocabulary processing; (2) there is a significant word frequency delay effect in Tibetan reading, which runs through the whole process of vocabulary processing; (3) there is a significant previewing effect of parafovea in Tibetan reading, through which the reader can extract speech and font information; and (4) in Tibetan reading, fovea word frequency affects the size of the previewing effect of parafovea—moreover, word frequency only affects the extraction of shape previewing information in the early stage of lexical processing, that is, the previewing effect of high-frequency words is greater under the condition of shape previewing. In conclusion, the effect of the processing load of the fovea on the previewing effect of parafovea shows the common characteristics of alphabetic languages in Tibetan reading. In addition, this study found that reading Tibetan involves the word frequency delay effect and the previewing effect of parafovea; these findings support the theory of parafovea sequence processing in the E-Z reader model.