https://www.theguardian.com/technology/2021/apr/04/online-games-ai-emotion-recognition-emojify
“The claim of the people who are developing this technology is that it is reading emotion,” said Hagerty. But, she added, in reality the system was reading facial movement and then combining that with the assumption that those movements are linked to emotions – for example a smile means someone is happy.
“There is lots of really solid science that says that is too simple; it doesn’t work quite like that,” said Hagerty, adding that even just human experience showed it was possible to fake a smile. “That is what that game was: to show you didn’t change your inner state of feeling rapidly six times, you just changed the way you looked on your face,” she said.