Collaborative serious games have proven to be effective learning environments to enhance the development of learners' soft skills, such as collaboration, negotiation and cooperation. To be effective, such role paying games should provide genuine interactions. However, little is known on how design choices, such as the viewpoint (either first or third person perspective), impact collaborative processes and learners' perception of their partners. This paper reports an exploratory study on the impact of the viewpoint on the sense of social presence, and on collaborative processes that emerge from learners' interactions in a collaborative serious game dedicated to soft skills training. To address this issue, learners played in either first-person or third-person perspective during a session of two games. Our results show that the first-person view allowed for a higher sense of social presence and increased information sharing. This seems to be mainly due to the knowledge asymmetry caused by the affordances of the environment, in other words design choices. These results can be applied in the design of collaborative serious games that support social interactions and collaborative skills training.