Is Senior Graduation Project similar to a Science Project?

Ok. So here's the deal. I have to think of a graduation project, and I have a general idea. My school allows us to pick any topic, as long as we can support our thesis with enough reliable sources, a la books, and internet articles. So, if I were to do an experiment on how video games affect cognitive ability in humans, would that be a viable project topic and thesis? Or do I have to choose something that's already been done?