Readers build a mental representation of text during reading. The coherence building processes readers use to build a mental representation during reading is key to comprehension. We examined the effects of self-explanation on coherence building processes as undergraduates (n = 51) read five complementary texts about natural selection and completed a post-reading measure of topic knowledge. Participants generated constructed responses (verbal protocols) while reading. We varied the use of constructed response prompt (self-explain vs. think-aloud) and constructed response format (typed vs. oral) to examine their impact on the quality of readers’ constructed responses and their coherence building processes (i.e., cohesion). Participants who received self-explanation instructions had higher quality constructed responses than participants who received think-aloud instructions, regardless of whether responses were typed or spoken aloud. Natural Language Processing (NLP) analyses indicated that participants who were prompted to self-explain generated more cohesive responses than those who were prompted to think-aloud. Participants who received self-explanation instructions had more coherent mental models during reading and typing was related to more cohesive responses when participants were asked to self-explain. Participants whose constructed responses were more lexically cohesive during reading had better performance on the post-reading test.