Paul Ekman's findings in universal facial expressions and emotions have always intrigued me not only because I'm interested but because of personal reasons too. My grandfather William Ayhan LeCompte was a psychologist and a colleague of Paul Ekman, and he helped Ekman in his research on the universality of expressions. I've always known this, but I decided to do some research on it, and I found an article that William LeCompte and some other psychologists wrote with Paul Ekman. The article is called "Universals and Cultural Differences in the Judgments of Facial Expressions of Emotion." In the lecture and the textbook, Paul Ekman's research in New Guinea to see if facial expressions are cross-cultural is mostly mentioned as a very important finding. However this article I found, further investigates this question and emphasizes in which ways the New Guinea research had problems.
The New Guinea research was not duplicated in other studies, and the expressions were artificial. The New Guineans were told to look sad like their child died, or look happy as if something good happened. The expressions weren't very accurate.
That's why Paul Ekman and my grandfather William Ayhan LeCompte and more psychologists further researched the universality of emotional expressions by showing 18 pictures to people from 10 different cultures and countries: Estonia, Germany, Greece, Hong Kong, Italy, Japan, Scotland, Sumatra, Turkey, and United States. The majority of people agreed on the expressions. This study is actually a lot more accurate and well-planned than the New Guinea study. This research provides a lot more evidence for the universality of facial expressions, and it actually proves it.
Here is the link for the article in case anyone wants to check out: http://www.paulekman.com/wp-content/uploads/2009/02/Universals-And-Cultural-Differences-In-The-Judgment-Of-Facia.pdf