Empath uses Galvanic Skin Response(or Skin Conductance), to allow two people to communicate on a level which is not usually available, mapping their stress/excitment level through to sound and light. It has been exhibited at Priceless, Lovetech, and Langton Labs Equilibrium event - Love. 

It's a more direct expression of music, and a more honest and direct communication of mood than talking, or facial expressions. Augmented communication. 

The second version of Empath, is an infinity mirror, with LED Bar graphs mounted inside which reflect into infinity, showing your excitement response as you sit opposite your conversational partner. It was shown at the recent Black Rock Arts Foundation Autumnal Gathering:2009.