Skill acquisition studies have generally focused on individual tasks, such as language learning, learning how to use a texteditor or how to play video games. Here we present a study that investigates how subjects learn to work in a team in adynamic collaborative task. The task - Coop Space Fortress - is a modification of a computer game used extensively inresearch, in which subjects fly space ships in a frictionless environment and coordinate to destroy a space fortress. Whenlearning to play this computer game, subjects not only master the game controls, but also typically settle on team roles tomore efficiently achieve their goal, despite not being allowed to communicate.