Social constructivism emphasises the role of meaningful interactions as a vehicle for learning. Meaningful interactions engage learners cognitively and socially with others to construct knowledge. Such interactions, however, require an environment specially designed to facilitate and guide learners' cognitive and social processes towards the construction of knowledge. Forums in massive open online courses (MOOCs) could potentially provide such an environment. However, research on how MOOC forums are designed to facilitate and guide cognitive and social processes is scarce. This study adopts a qualitative lens to examine the specifications, pedagogical instructions, and guidance provided in the forums of 4 edX MOOCs to help learners engage in meaningful interactions. We sought to uncover how MOOC forums are designed to support the social construction of knowledge. We found that MOOC forums mainly seek to facilitate cognitive processes while giving scant support or guidance to social processes. Such a learning design might favour the individual over the social construction of knowledge. To a certain extent, our findings help explain the questionable effectiveness of MOOC forums as social learning environments.