"An introductory exercise was meant to familiarize the actors with the personality. Then, the actors were asked to act out situations—as if they were the robot vacuum cleaner—making use of motion and sound (expression through light was taken into consideration only after this exercise). In general, the actors either crawled about or walked around at a slow pace to imitate a vacuum cleaner. Often, a typical vacuuming sound was simulated by them."
Once they finished laughing at the actors (and, later, over biers, at the video), they called in a group of 15 volunteers to watch a boring square "vacuum" that was actually a remote-controlled fake vacuum, fail to clean up the room as usual, but do so while exhibiting the personality traits desired by the researchers and portrayed by the actors.
What they discovered – other than that actors have no sense of shame at all, and that most people can't tell a robot with a programmed personality from a remote-control white square box being driven by an emotionally manipulative Norwegian graduate student – was that the personality characteristics displayed by the robot did make a difference in how positively it was perceived by volunteers.
This is a revolutionary finding no one could have predicted from the celebrity of "robot" characters with fake personalities like C3PO, R2-D2, Wall-e, or the entire cast of Twilight.
Given its positive results, it's a little sad that "Robot Vacuum Cleaner Personality and Behavior" (PDF) was published in the "International Journal of Social Robotics" in April, but largely ignored until it was written up in Annals of Improbable Research, sponsors of the IgNobel Awards, the Luxuriant Flowing Hair Club for Scientists and other celebrations of legitimate but silly or pointless science.
When asked what it thought of the study and its findings, the robot vacuum beeeped plaintively and spewed smoke from a source that might have been indelicate had it been anything but a robot.