Paul Akman created a system to read faces, emotions, spot lies...
The TV series Lie to Me was based in his studies. He found there was facial muscle reaction involved in feeling that was universal. This image mosaic of faces it's exaggereted, and there are many other few expressions that took just a fraction of secnd or that are a lot more discreet, but spots emotions of many kins.
I bet people in future will be charged by facial conducts.
Take the face expression computer recognized, smells sensors too, and sexual phenormonium reactions, made by computers put on glasses, connceted to web in real time. Jesus... Any male who teachs in a class with 17 year old girls would be finished, f... of.