The purpose of the current studywas to explore social and cognitive relationships among studentswhen they are solving complex cognitive tasks in online discussion forums(self-regulated). An online course targeting interventions for risk behaviorswas developed in the Virtual Campus of Andalusia, Spain. A total of 9878 units of meaning posted in 96 online discussion forums during three academic years (2010–11, 2011–12 and 2012–13) were analyzed through the Community of Inquiry (CoI) framework. The degree to which online tasks at three different levels of cognitive demand (analyze, evaluate and create) triggered cognitive and social processes were examined. The results indicate that there was a specific increasing trend in the frequency of cognitive and social activity according to the requirement of the task. This study also found that the nature of the learning taskmodulated the different components of social and cognitive presence in these contexts.