The same facial expression is used across different languages and cultures to represent a negative feeling, scientists have discovered. The 'not face', as they call it, was identified in native English, Spanish, Mandarin Chinese and American Sign Language (ASL) speakers whenever they expressed disagreement.
Published in the journal Cognition, the study investigates Darwin's theory that the ability to communicate danger and aggression was crucial to human survival. The authors believe that truly universal expressions are most likely to represent negative emotions.
Verified in the four groups of native speakers studied, the hypothesis describes the 'not face' as a combination of a furrowed brow, pressed lips and a raised chin. The expression was so instinctive in all participants that the scientists found it was used at the same frequency as words.
Response to negative statements
In total, 158 Ohio State students were recruited to participate in the research. The scientists instructed them to sit in front of a digital camera, and to have a chat with the person filming them, in their native language.
The researchers used the recordings to associate grammatical markers of negation and disagreement ( like the word 'not') to facial expressions. To achieve this, they manually tagged images of the students speaking, frame by frame, to identify which facial muscles were moving and how. Computer algorithms were then used to analyse the frames and find similarities among them.
This is how the scientists discovered the 'not face'. More importantly, the experiment asserts that, regardless of the language spoken or signed by the participants, this facial expression always accompanies grammatical signs of negation, and disagreement.
Just like a word
The scientists also measured the frequency at which the students expressed the 'not face'. Typically, speech speed varies between three to eight syllables per second, or 3-8hz. From their recordings, scientists established that the students' facial muscles all moved to make the 'not face' within this same frequency band.
This suggests that the face itself functions as a universal grammatical marker of language. It is used to express an emotion in the same way, and at the same rhythm as a word.
This usage of the 'not face' was even apparent in people communicating in ASL – as they only speak in signs, they usually shake their head to express negation. However, the scientists noted that some participants preferred to use the 'not face' instead to emphatically mark negation in their sentence.
The scientists believe other universal faces exist to express positive feelings, but they say it will be harder to identify them. "That will likely take decades," lead author Aleix Martinez warned. "Most expressions don't stand out as much as the 'not face'."