External representations can be powerful for supporting learners in both individual and collaborative learning scenarios. They encourage learners to focus on important instructional elements. In this study, we investigate two different forms of external representations: textually represented collaboration scripts and graphically represented content schemes. Fifty-three triads of university students are assigned to four experimental conditions involving the factors "collaboration script" and "content scheme". Results show that learners particularly benefit from the content scheme. Its graphical elements help focus the learners' collaboration and they therefore achieve better outcomes. (Contains 4 tables and 3 figures.)