I think this is an interesting topic to investigate. One way to proceed is to learn what psychology can tell you about detecting truth vs lie in body language (see website). Then you can ask for volunteers to participate in your study. Once you have the volunteers, randomly assign them to tell you the truth or to lie about something, for example, their first pet, or their experience in 5th grade, whatever. Then use what you have learned and see if you can tell the liars from the others. Keep a record of your results and what clues gave the volunteer away. Of course there are other ways to do an investigation too. Good luck.