This study investigated the effects of example-postings on students' cognitive load and performance in online discussions. Cognitive overload was assumed had caused the problem of the lack of reflective and thoughtful contributions in student discussions. The theoretical foundation supporting the use of example-postings aiming at reduce cognitive load and therefore improvement student performance was cognitive load theory. Example-postings demonstrated good ways to follow the discussion rubric that were stated in abstract manners and were provided as part of the discussion instruction. These examples were highlighted with explanations on the purpose of each section and what requirements in the rubric were met. Other than examining the effects of example-postings, this study demonstrated the procedures of using 2X2 cross-over experimental design and the analysis methods. The use of cross-over design was to improve the power of the study without increasing the number of participants. Several effects that were associated with the cross-over design, including cross-over effect, task effect, and treatment effect were analyzed separately. Grouping effect was also analyzed. The results of this study showed that the students did not perceived very high level of cognitive load in either the treatment (with example-postings) or the control (without example-postings) condition. The use of example-postings did not reduce cognitive load of the discussion instructions but improved students' performance in the discussions. This findings indicated that with the increasingly broadly use of online discussions, students were more experienced with this instructional activity therefore cognitive overload was less likely a problem. Without investing more mental effort, the students were able to construct more thoughtful and reflective postings in the online discussions when example-postings were presented. This finding implies that the example-postings helped the students better understand the discussion requirements and affected the ways students organize and presenting their thoughts and ideas. The significant carry-over effect also confirmed the positive effect of example-postings by showing that the students learned from the examples and were able to transfer the learned knowledge and skills to new tasks. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]