The transposed-word effect persists across text orientations in Chinese

In speeded grammaticality decision tasks, the transposed-word effect occurs when ungrammatical word sequences created by swapping adjacent words in an otherwise grammatical sentence are harder to reject than control sequences derived from ungrammatical base sentences, providing evidence for flexible word-order processing during reading. Previous research shows that this effect is often attenuated in atypical display formats, including serial word presentation and backward text, especially in RTs. Some accounts interpret this pattern as a shift from parallel processing, in which multiple words are recognised simultaneously, towards more serial word recognition. However, atypical formats may also disrupt component processes supporting reading, including eye guidance, spatial attention, and parafoveal processing, thereby reducing the uptake of information from adjacent words. We extended this work to Chinese, a script that can be read in horizontal and vertical orientations while individual characters remain upright. Two hundred native Chinese readers made speeded grammaticality decisions to five-word sequences presented left-to-right, top-to-bottom, right-to-left, or bottom-to-top. Robust transposed-word effects occurred in both accuracy and RTs across all orientations. Effects were largest for conventional left-to-right text and smaller in all three atypical orientations. Thus, attenuation occurred even though all words remained simultaneously visible. It was therefore not confined to formats that physically enforce serial presentation. Although attenuation may reflect a shift towards more serial word recognition, it could also arise because difficulty processing atypically oriented text narrows spatial attention and reduces parafoveal information uptake. These component-process changes can occur under either parallel or serial accounts, making the findings compatible with both.