For the upcoming questions, the investigator is the person who is responsible for overseing the day to day operation of the study--this might be a research coordinator in some cases. The primary experimenter is the person who actually tests the participants. Additional researchers (e.g., undergraduate RAs) can be added as assistants to the project later. The Principal Investigator is a faculty member who oversees the project. If you have any questions about whose name to put where, please ask, ideally BEFORE submitting this form.