If we're going to talk about using to detect emotional reaction in individuals on the street you could walk by a pretty lady (or gent depending on who's reading

If we're going to talk about using to detect emotional reaction in individuals on the street you could walk by a pretty lady (or gent depending on who's reading this) and determine if they show any signs of arousal/disgust when they see you. The science of human emotion when paired with this technology would be particularly interesting on its own.