Middlemist, Knowles, and Matter (1976) conducted a study investigating whether or not invasions of personal space are physiologically, as well as psychologically, arousing. The study was conducted in a men's lavatory. Men were randomly assigned to have personal space or to have their personal space invaded. The investigators closed off specific urinals. Participants were forced to urinate either in the urinal next to a male confederate or in the urinal one away from the confederate. A second confederate positioned in a toilet stall adjacent to the urinals observed the subjects via a periscope and recorded the latency to onset of urination and its duration. 3. What type of research design is being used (i.e., descriptive, correlational, experimental)