Not a new thing, has been worked for decades. Talked to related work at MIT to leverage these ideas. But we are getting much better at it now. Much written about it here. In ChainstoreAge:
Is Facial Recognition in Retail Market Research the Next Big Thing? by Terry Lawler
" ... One of the hottest areas of technology development in retail research is facial and emotion recognition. Understanding emotions is powerful in areas of research such as ad testing, but difficult to achieve. Facial expressions are linked to emotions, and research organizations have used human observation of recorded videos in retail settings to try to assess emotional response for years. Human assessment has many limitations, and facial expression recognition technology offers an opportunity to overcome some of these limitations, delivering a much greater level of insight about personal sentiment and reactions.
Organizations managing research programs and retail customer experience activities can use emotion detection technology to analyze people’s emotional reactions at the point of experience. This knowledge not only gives researchers a greater understanding of behavior patterns, but also helps predict likely future purchasing actions of that consumer. .... "