Dan Ariely's TED Talk deals with the idea that we really don't know how to control our own cognitive abilities as much as our physical abilities.
He presents this idea with some optical illusions and some example decisions to show how in some instances, we might not really be in control of what we decide to do. One of the more compelling examples that he presented was towards the end. Where he gave us two sets of pictures with two CGI faces of the same name. One was named Tom and the other was Jerry. He then proceeds to tell the audience what the experiment was actually about. It was all about how people choose who was more attractive between the two. Then he proceeds to add another option in the middle of the two faces, which is just an uglier rendition of Jerry in one and Tom in the other set. It showed how whichever had the uglier rendition of themselves had the higher chance of getting picked with their normal face.
This one was a bit harder to pinpoint on how this related to tragedy, but I think I have a bit of an idea. The best way I can represent my idea is with the story of "Oedipus Rex." No matter how much he tried to avoid his fate of becoming the doom bringer to his own life and to others around him, his choice did not matter because fate had already set forth a path for him in that however he wanted to divulge from that path, he would always go towards the same outcome. this is where the true tragedy of Oedipus really lies I think.
This TED Talk didn't really challenge what I thought of Tragedy, though it did manage to get me thinking about Oedipus' story more, so that was neat.