Also, for those skeptical: There's something in human psychology field called "Emotional Facial Action Coding System" (EFACS). Our bodies "talk", especially our faces, and we call it "body language". There are some specialists (psychologists) that are capable of "reading" such language. Mentionable specialists are Paul Ekman (PhD) and Joe Navarro (ex-FBI and author of "What Every Body Is Talking"), as well as those within my country Vitor Santos ("Metaforando") and Ricardo Ventura ("Não Minta Pra Mim"). There are broader specialists capable of such nonverbal reading as well, such as Derren Brown, responsible for documentaries such as "The Push". Specialist humans are good at this, but AI is capable of detecting even subler movements. Have you noticed a camera always pointed to our faces (we call it the "selfie camera")? It's like having a Paul Ekman seeing your face 24/7, one that is capable of reading your nonverbal behaviors so precisely that he could actually "deduce" what exactly are you thinking.