Don't believe your ears!

By combining tones you can create a tone that is not there at all! And there is a tone that seems to go up forever. How is that possible? By taking advantage of the way our ears receive and process sound, our ears can be tricked. The direction, the composition of tones and the volume of the sound play a role in this. But the shape of your auricle, your expectations and your age are also important. Neurophysicist John van Opstal explains how your ears work by showing why they sometimes don't work during his lecture in the series of "Radboud sounds".