This work is funded by the Swiss National Science Foundation (Research contract 1114-040711.94). We would like to thank members of the TECFA Unit (especially Daniel Schneider and Patrick Mendelsohn) for helpful discussions on the issues presented in this paper, for software and hardware support, and for helping playtest the problem tasks. We would also like to thank Kayla Block and Richard Godard for advice and help implementing things in TECFAMOO. We also express our gratitude to the subjects who participated in our experiments.