The goal of the experiment described in this report was to assess possible effects of the possession of a shared mental model on team decision making. Cross-training in each other's tasks was chosen in the experiment as the means to induce a shared mental model. The effects of cross-training were studied in a two-person team task. In this task, one of the team members acted as observer who had to detect and report fires in a city to the other team member who acted as decision maker by sending fire engines to the fires. Team members communicated via standard computer messages. Dependent variables were performance measures (number of victims, efficiency of allocated resources) and communication measures (number and type of messages sent). The results showed some effects of cross-training but not the predicted effect of sending more unrequested information to the other team member. This was probably due to the observer being not dependent enough of the decision maker for performing his task. Some suggestions are made to improve the paradigm and obtain more mutual dependence with the team members.