This study analyzes 51 papers on cognitive engagement in asynchronous discussion forums, focusing on their use in educational technology. It categorizes the research into three main areas: students' attitudes towards ICT for learning (17 papers), methodologies used in the field (16 papers), and knowledge construction processes in online discussions (18 papers). The analysis reveals that most studies reported a low level of cognitive engagement in students' knowledge construction. The effectiveness of online communication in education is found to heavily depend on the design of classroom processes and the roles of teachers in guiding student participation in asynchronous discussions.