Flexible Coding of Morpheme Position Information in Tibetan Reading: Evidence from Eye Movements.

Morpheme position information, referring to the relative sequential order of morphemes within a word, is crucial for word recognition and reading comprehension. Tibetan combines alphabetic and ideographic features, but it remains unclear whether morpheme position information is processed in Tibetan reading, whether the transposed-letter effect manifests itself, and how lexical access is represented for Tibetan two-character words. We conducted two eye-tracking experiments to address these questions. In Experiment 1, in the identical condition, all temporal eye-movement measures were the shortest, with the largest progressive saccade amplitude and the fewest number of fixations. The transposed condition ranked second, whereas the substituted condition resulted in the longest temporal measures, the smallest progressive saccade amplitude, and the greatest number of fixations. Experiment 2 showed a consistent pattern with Experiment 1, and no interaction was observed between presentation type and word frequency. The two experiments jointly indicated that morpheme position information is processed during Tibetan reading. Transposed nonwords activate the base word more readily than substituted nonwords, suggesting that morpheme decomposition serves as the key pathway for word recognition. This study provides the first empirical evidence for morpheme position information processing and the transposed-letter effect in Tibetan reading, supporting the decomposed morphological representation view.