過去詞彙邊界研究常藉插入或移除詞間空格，來觀察對閱讀表現的影響。在拼音書寫系統裡，詞間空格透過降低首尾字母側抑制效果、提供詞長資訊和清楚的眼跳目標來提升閱讀表現。而在原本就無詞間空格的書寫系統插入詞間空格後，於閱讀表現上並無如同拼音文字明顯的差異。Bai、Yan、Liversedge、Zang及Rayner（2008）提出相互抵銷假說來解釋：當插入詞間空格時，有助於詞彙辨認處理，但因呈現方式為讀者不熟悉的形式，進而產生干擾。這兩類效應相互抵消，導致插入空格時的表現與閱讀一般文章相仿。然而，插入字元大小的空格，將影響詞彙預視品質，並加大眼球移動控制誤差。因此，本研究透過方框，在不變更文字排列以及維持每個詞彙的背景對比下，將中文字串區斷為有效詞邊界、無效詞邊界、字元邊界及控制組，透過邊界線索類型對閱讀眼動表現之影響，探討詞彙與字元表徵在閱讀中文文章時的運作方式。結果顯示詞彙為閱讀時主要處理單位，尤其在資訊整合階段。而在詞彙辨認早期階段，發現字元邊界組無干擾效果，指出字元在早期視覺辨認中的角色。本研究並進一步釐清相互抵消假說，透過延遲效果（lag effect）與前置效果（successor effect）探討干擾與助益效果可能來源。

The insertion or omission of inter-word spaces is used to investigate the role of word boundaries on reading performance. It has been argued that inter-word spaces in reading alphabetic languages improves reading performance by reducing the lateral inhibitory effects of the first and last letters of a word; inter-word spaces also provide word length information making words salient as the saccade targets. For language scripts without spaces, it has been shown that the insertion of inter-word spaces does not cause a significant disruption in reading performance. Bai, Yan, Liversedge, Zang, and Rayner (2008) suggested a mutual-offset hypothesis to explain the indifferences between reading spaced and unspaced Chinese sentences. That is, when inserting spaces between words, word processing is enhanced, but the unfamiliar spaced text causes certain interference. The effects cancel each other and result in the lack of differences between two conditions. However, the insertion of whole character spaces in their study might affect the quality of preview processing and increase the amount of oculomotor errors. The present study used frames to provide segmentation cues for the string of characters into four types of perceptual grouping (word, non-word, character, and full line) without changing the spatial layout of characters. The goals of this study are: 1. to investigate whether word or character is the meaning unit during reading Chinese; and 2. to examine the mutual-offset hypothesis. The results showed that words were the main process units during reading Chinese but characters may play a role at the early visual processing. Moreover, the analyses of the lag and successor effects examined the mutual-offset hypothesis and shed some light on the possible sources of interferences and benefits for providing word segmentation cues in reading Chinese.