Online learning is increasingly prevalent in higher education. The current study explores how learning takes place in online discussions; an activity often found in online courses. Activity Theory is used to understand the contributions of individuals to the process of socially constructing knowledge within small groups. The Community of Inquiry (CoI) model and the Interaction Analysis Model (IAM), support the identification and analysis of individual contributions to discussions along with group level dynamics. The CoI integrates the social, cognitive, and teaching aspects of the online discussion through the concept of presence. While it is largely recognized that each participant can contribute to the learning of others in the group, teaching presence on the part of students is rarely examined. How does teaching presence on the part of individuals contribute to social construction of knowledge within groups in online discussions? This study examines online discussions within a graduate level human development course. A total of 334 messages from 27 participants are coded for evidence of social, cognitive, and teaching presence at the individual level, and phases of construction of knowledge at the group level. This allows for multi-level comparative analyses of the contributions of individuals to interactive processes within groups. Data reveal that students do in fact engage in teaching presence within online discussions, and that this is beneficial for the social construction of knowledge within small groups. Instructor modeling contributes to establishing community and supports teaching presence on the part of individual students and the social construction process in groups. The findings have implications for the design of online discussions, the instructor's presence and role in supporting learning, the design of and future research on teaching and learning, and the practice of child development professionals. [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.]