Pinocchio's Lie Detector Test By Sara Madden Finished: November 27, 2014

Scientific Question Are there changes in the brain someone is lying or telling the truth?

Background The reason I chose this project is because the scientific question really intrigued me, and I had recently read into lie detector tests used by police forces, and how they aren’t always 100% correct. So I figured I’d try a little homemade one to see my own results. It obviously wouldn’t be 100% accurate, but it’d be cool to see if telling a lie could impact a person’s ability to do small physical tasks, like resistance.

Hypothesis If I ask the volunteer to repeat a truthful statement, then the resistance will be greater than if they had lied.

Variables Independent: Whether the volunteer is telling a truth or a lie Dependent: The resistance of the volunteer Controls: The amount of pressure administrated, the volunteer’s truth/lie, and the volunteer

Procedure Ask volunteer to state three things they like, and three things they dislike. Place arm on volunteer’s outstretched arm and ask volunteer to repeat a truthful statement. Repeat step two with an untruthful statement Record results Repeat steps 1-4 with other volunteers

Data Volunteer One Yes Volunteer Two Volunteer Three No Volunteer Four Volunteer Five

Conclusion Upon testing the question, “Are there changes in the brain someone is lying or telling the truth?” I found that three of my five volunteers gave more resistance when performing a physical task, in this case, me pushing on their arm, when they were repeating a truthful statement. This supports my hypothesis. If I were to redo this experiment, I would try maybe a more difficult physical task, and a more personal question to interact with the brain more. Concluding this experiment, I infer that the reason why I got my results is because when lying, the brain is more focused on trying to hide the lie then focusing on the physical task.