But for the most part, it’s Ekman’s fundamental idea—that emotions are the same for all humans across cultures—that tends to provoke the most criticism. Decades before either Barrett or Russell criticized his model, he was catching flak from the famous anthropologist Margaret Mead, who believed emotions were a product of culture. “[Mead] treated me rather shoddily,” Ekman says. In a 1975 issue of The Journal of Communication, Mead wrote a disparaging review of Ekman’s book Darwin and Facial Expression, calling it “an example of the appalling state of the human sciences.”

“I never found out whether she was making a pun on my first name,” Ekman says, referring to the “Paul” in “appalling.”

But emotions don’t exist in a vacuum, and for some researchers, context is everything. (Though, for what it’s worth, Ekman does concede that the basic toolkit of emotions all humans share can be influenced by experience.) “When people across cultures have the words for anger, that doesn’t mean that anger means the same thing, that it evolves in the same way, that the same situations are thought to be anger, that how anger functions in a relationship is similar,” says Batja Gomes de Mesquita, director of the Center for Social and Cultural Psychology at the University of Leuven in Belgium.

When Mesquita considers Ekman’s photos, she says, “it’s not clear to me that what these faces express is emotion. But it’s undeniably the case that what they express is relevant to emotions. I think a lot of the problems are not so much in the data, but in the inferences from those data.”