Is There a Reliable Correlation Between Facial Expression and Emotion?

The idea that a smile equals happiness is so problematic it has been used in the past to try and detect which people might be under stress. In fact, the spot system was one of these systems that was inspired by echman's thinking - but also very racially biased. So i think in many cases, these sorts of systems actually need much stronger regulation and, frankly, much more scientific debate.