A ready smile, well-applied eye make-up and a dash of youthful vigour are useful components for a successful run for elected office, according to studies into the nature of trust – the most elusive of modern political traits.
Researchers from Paris universities used an algorithm built upon known facial traits that prompt feelings of trust – such as a smiling mouth or wider eyes – and tested it for accuracy on databases of human faces separately assessed by human volunteers.
They used the algorithm to assess thousands of portraits from the 14th century onwards to conclude that people found prominent figures more trustworthy as centuries passed and societies became more prosperous.
The smile was a key element to winning trust with the depiction of stern, patrician leaders changing with a “smile revolution” in portrait styles in 18th century France, according to the study published on Tuesday.
“If you’re smiling, you have a higher chance of being trusted,” said Lou Safra, one of the researchers.
Which of today’s famous faces does the algorithm trust?
The National asked the academics to use their algorithm to assess the perception of trust in a modern-day group of leaders and influential figures.
The researchers first ran an experiment on photographs of a smiling US Democratic presidential candidate Joe Biden and an unsmiling shot of the incumbent, Donald Trump. The algorithm gave Mr Biden a trustworthy rating while ranking Mr Trump as untrustworthy.
The National sent in a series of photographs which were transplanted on to avatars to evaluate the subjects' level of trustworthiness. The team was then able to rate the following 10 leading figures:
The programme came up with the two most and the two least trustworthy. The results are at the bottom of the article but here you can guess the most trustworthy pair.
The research team said the results would be altered if different pictures were used, and also that women and younger people are more likely to be rated as trustworthy.
Ms Safra said cosmetics that make the eyes appear bigger, and judiciously applied lipstick, could alter one’s appearance sufficiently to make a person appear more trustworthy.
Researchers said the latest study tracked changes in the style of prominent people, who in past centuries wanted to be perceived as unsmilingly steadfast and harsh, to the modern political era, in which many leaders seek public approval at the ballot box.
“If people smile it’s because they want to inspire trust, display co-operative features and show themselves as good co-operators,” Ms Safra said.
Most trustworthy: Meghan Markle and Emmanuel Macron
Least trustworthy: Pablo Escobar and Vladimir Putin