A smile is the universal welcome, the writer Max Eastman once remarked. But how sure can we be that a person’s smile is genuine? The answer is the empathy test, created by psychologist Richard Wiseman, which probes our ability to appreciate the feelings of others – from their appearance.

A photographer asks a subject to imagine meeting an individual they don’t like and to put on a fake smile. Later the subject sits with a real friend and as they converse, the photographer records their genuine smile. Thus two versions of their smile are recorded.

The question is: how easy is it to tell the difference? “If you lack empathy, you are very bad at differentiating between the two photographs,” says Wiseman, who teaches at the University of Hertfordshire.

But how do professions differ in their ability to spot a fake? And in particular, how do scientists and journalists score? Neither are particularly renowned for their empathy, after all. Last month’s Scientists Meet the Media party, for which the Observer is the media sponsor, gave Wiseman a perfect opportunity to compare the two professions.

At the party, hosted by the Science Museum in London, some of Britain’s top researchers mingled with UK science journalists. About 150 guests were shown photographs of subjects with fake and genuine smiles. Guests were then asked to spot the false and the true. The results were intriguing.

“The public normally gets around 60% right, which is above the chance level of 50%,” says Wiseman. “Partygoers got 66% which is significantly higher while there was some difference between age groups: under-40s did slightly better than over-40s.”

However, the real difference came with professions: physical scientists got 60% right; biological scientists 66% and journalists a very impressive 73%. But they were all eclipsed by social scientists, with 80% – though only four took part, making their results less significant.

As to the difference between the two photographs above, it is the one on the right that is false. “You use more face muscles when you have a genuine smile and you see that in the lines round the eyes of the subject which crinkle up more,” says Wiseman. The eyes have it, in short.