Is this the latest craze in headgear? A Japanese device shows your mental state via a pair of ears that change direction based on your mood. Neurowear is the name of a project to develop fashion items and gadgets using brain waves and other biosensors. 

How does it work? Brain activity creates electrical impulses. A sensor in the headgear interprets the impulses and translates mental state into ear movements. This video, which 2.6 million people have watched as of mid August, shows how it works.