Out of thousands of possible facial expressions, only 35 are universal, carrying the same meaning and interpretation across cultures. Of these, nearly half are facial expressions associated with happiness, which “speaks to the complex nature of happiness,” researchers say.
“Happiness acts as a social glue and needs the complexity of different facial expressions; disgust is just that: disgust,” said study co-author Aleix Martinez, PhD, a cognitive scientist and professor of electrical and computer engineering at The Ohio State University.
Research into visual communication of emotional states is an expanding field of study. Combined with improved facial recognition technology, such research is expected to inform the development of emotionally ‘smart’ AI.
Martinez and co-author Ramprakash Srinivasan, a doctoral student at Ohio State in Martinez’s lab, ran computer simulations to determine the human face is capable of more than 16,000 facial expressions. They then compiled a list of 821 English words that describe emotional states. With the help of professional translators, they translated these words into Spanish, Mandarin Chinese, Farsi and Russian, and ran each list of words through 31 global search engines to compile a database of 7.2 million images representative of these words across a variety of cultural contexts.
They then sorted the 7.2 million images into categories, looking for pan-cultural matches in facial expression and emotional state — and finding only 35. Half of these 35 expressions were related to happiness; one was an expression of disgust, three expressions conveyed fear, four conveyed surprise, five conveyed sadness, and another five conveyed anger.
“We were shocked,” Martinez said. “I thought there would be way, way more.”
They found eight more facial expressions that were similarly identifiable within several cultures, but not all. These expressed positive and negative emotional states outside of the six feelings above.
Martinez and Srinivasan concluded that, while thousands of facial permutations are possible, humans likely use many fewer facial expressions to convey emotional states, most of which cross culture and linguistic barriers.
The study is not without major limitations, however. The study did not include images from African cultures, because, the authors said, few candid photos exist online from within those contexts, compared with other geographies. Which means roughly 16% of the world’s global population wasn’t considered in the study. This might seem like a small percentage, but in a global study, it isn’t; it’s an entire continent of 1.2 billion people, with a vast range of cultural milieus.
