Humans practically have a "sixth sense" for sniffing out corrupt politicians. A new study by Caltech researchers shows that people are capable of making “better-than-chance judgments” about whether a politician has been convicted of corruption just based on a photograph of their face, even if they don’t know anything about their careers, personality, or political beliefs.

In particular, the findings suggest that it’s all to do with their face shape. State officials with wider faces, or a higher facial width-to-height ratio, tended to be picked out as the most corruptible. 

This new research mirrored previous findings, suggesting that politicians with wider faces were perceived as being more corruptible, aggressive, and selfish but competent and ambitious. There were some other factors that slightly swayed people’s opinion, such as the intensity of their smile and their choice of facial hair, but their effect was relatively insignificant.

"It might be difficult to understand why you can look at others' faces and tell something about them," co-author Chujun Lin said in a statement. "But there is no doubt that people form first impressions from faces all the time. For example, on dating sites people often reject potential matches based on pictures without reading the profile."

The study, published in the journal Psychological Science, reached these conclusions through a series of experiments. In the main experiment, 100 participants looked at headshots of 72 politicians who held office at the state or federal level, half with corruption convictions and half with clean records. They were then asked to rate each politician on how corruptible, dishonest, selfish, trustworthy, and generous they looked.

Almost 70 percent of the time, the people were able to correctly spot a corrupt politician from a clean one.

Then they compared the data from the previous experiment and analyzed how it paired up with eight different facial measures. Low and behold, it was the wider faces that were most often picked out as corrupt.

However, bear in mind, having an angelic face may not mean they've never taken part in corrupt activities, and vice versa.

As the researchers explain, an official with an appearance perceived as "untrustworthy" might just get approached more often with corrupt offers. Furthermore, they are more likely to be investigated and perhaps a jury is more likely to convict them.

"If a jury is deciding whether or not a politician is guilty, having a corruptible-looking face might create a negative impression, which might influence the jury's decision,” added Lin.

Equally, although first impressions are significant, we all base our opinions about a person’s trustworthiness on far more than a static photograph of their face. Our perceptions of people are based on every facet of their being, from the way they walk and smile to the tone of their voice or their personal history.