Chat‐based Computer Supported Collaborative Learning (CSCL) often suffers from limitations due to the communication medium. A frequently reported consequence is the lack of discourse coherence and by this a lack of cognitive coherence in the learning process. To overcome these deficiencies, the implementation of explicit references with chat messages caused higher learning results. However up to now, we do not know enough about the responsible cognitive processes. In this experimental study, we analysed eye movements during a chat‐based CSCL scenario to gain indications of learners' use of references. The results allow implications for a modified design of (chat‐based) CSCL.