Is there really such a thing as human nature, or are all of our thoughts and instincts just the product of cultural conditioning? This is a question that has kept philosophers and anthropologists in a job for thousands of years, but new research may have just shifted this age-old debate closer to a conclusion, by revealing that the meanings of certain facial expressions are not universal, and can instead vary between cultures.

Though the ability to read the body language of others is often taken for granted as an innate skill, the results of a study published today in the Proceedings of the National Academy of Sciences indicate that intuitive forms of social communication are not pre-programmed into our consciousness, but are in fact acquired. Such a finding adds considerable weight to the concept of cultural relativism, which holds that we as humans are not inherently compelled to feel or act in any particular way, and are instead molded by our surroundings.

A team of researchers showed a series of photographs depicting a range of facial expressions to children from the Trobriand Islands of Papua New Guinea, chosen for their isolation from Western culture, and asked them to identify the emotions being depicted in each image. Surprisingly, the children consistently attributed feelings to these faces that contradicted the answers given by another group of Western children based in Spain.

The study authors were particularly staggered to find that while the Spanish children were able to recognize a “gasping” face as an indicator of fear, the Trobrianders tended to view this expression as a sign of anger or threat.

In a follow-up experiment, the researchers showed both groups another series of pictures and asked them to pick out the threatening face. As expected, the Spanish children regularly selected the “scowling” face, but the Trobriand children were much more likely to opt for the “gasping” face.

Based on these results, it is thought that certain aspects of social communication that are often assumed to be natural are in fact learned, suggesting that much of what we thought we knew about the human condition may just be the product of cultural programming.

More specifically, the study authors insist that their findings "should lead researchers to reconsider the assumption that a 'fear' gasping face is a uniform, pancultural index of fear."