In an empirical study, we provided (or not) pairs of students working in a remote collaborative learning situation with a knowledge awareness tool that provided learner A with learner B’s level of knowledge measured through a pre-test. We analyzed the effect of the knowledge awareness tool on asymmetric pairs with regards to the prior-knowledge. Post-hoc analysis on the pairs’ knowledge level showed that the knowledge awareness tool mainly affects the learning performances of asymmetric pairs. Further analysis on the learners’ level showed that the knowledge awareness tool mainly affects the collaborative learning gain of the more-knowledgeable peers of asymmetric pairs. The results are discussed in light of socio-cognitive processes such as audience design and perspective taking.