Discourse Connectives and Lexical Cohesion: An Experimental Investigation of Bi-Clausal Sentence Processing in Turkish

It is a widely accepted fact that coherence enables a text’s comprehensibility. A major source of coherence is discourse cohesion (textual properties of the text). Lexical cohesion (e.g. synonymy) and discourse connectives are two major types of discourse cohesion. We investigate the contribution of these two types of cohesion to the overall comprehension of bi-clausal sentences in Turkish. In a two-phase study, we ask the participants to judge the comprehensibility of sentences while we obtain eye-gaze data and then ask them to write recall protocols. We find that lexically cohesive sentences (labeled as high coherent) are judged more comprehensible and recalled better, and that in low coherent sentences (those lacking lexical cohesion), the fixation counts are high. This study shows that in short texts, lexical cohesion guides coherence and it is singled out as an important factor of discourse comprehension. The study concerns Turkish discourse and may have implications on discourse coherence and discourse comprehension in other languages.