Despite the importance of improving students' ability to learn from text, relatively little research has been conducted on motivational and instructional aspects of text learning, especially in real classroom contexts. The present study aimed to obtain a more comprehensive picture of the motivational and cognitive processes involved in children's text comprehension in natural classroom learning environments. Participating in this study were 182 fourth grade children, who were assigned to one of the three treatment conditions: Collaborative Reasoning, Conventional Discussion, and No Discussion. Results revealed that Collaborative Reasoning enhanced children's interest in classroom discussion whereas Conventional Discussion increased children's interest in reading. A number of factors were found to predict emergence of interest experience in discussion, including approach to classroom discussion, children's reading proficiency and prior interest in classroom talk, as well as their feeling about the text used in the discussion and their engagement in the discussion varying across time and situations. Children didn't differ significantly in their performance on text comprehension as assessed in a sentence recognition paradigm. However, children in both Collaborative Reasoning Discussion condition and Conventional Discussion condition outperformed children in the No Discussion condition in the quality of essays written at the end of the study, including produced number of words, number of relevant arguments, number of counterarguments, and number of rebuttals. Although no difference in length and number of arguments generated in the essay, children in the Collaborative Reasoning condition produced significantly more counterarguments and rebuttals than their counterparts in Conventional Discussion condition. However, the mediating role that interest and motivation might play between classroom learning environment and children's deep-level learning was not supported by this study. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]