When it comes to making snap judgments about people based on their faces it turns out that as a species we’re remarkably consistent: certain jaw lines or smiles really do make people think someone is more controlling or approachable, even though these traits might not be borne out in reality.
To find out how facial features influence first impressions, researchers from the University of York created a database of cartoon faces based and used mathematical models to measure and tweak 65 different factors - everything from eyebrow length to jaw shape.
They then asked volunteers to rate the faces based on three ‘core’ social factors: attractiveness ("Would this person be a good romantic partner?"), dominance ("Are they capable of carrying out those intentions?") and approachability ("Will this person help me or harm me?")
They found that certain physical features could strongly predict peoples’ judgements. For example large eyes were associated with attractiveness, masculine facial features with social dominance and a big smile with approachability.
University of York neuroscientist and senior author of the paper Dr Tom Hartley said that these associations were not surprising in themselves but that the consistency of people’s reactions could be important in a world where first impressions are increasingly based on profile pictures on the likes of Tinder and LinkedIn.
“It might be problematic if we're forming these kind of judgements based on these rather fleeting impressions," Dr Hartley told the BBC, "particularly in today's world where we only might see one picture of a face, on social media, and have to form our impression based on that."
He added that the findings could also be beneficial to people looking to put their best face forward in business or in socializing.
“You would be able to use these kind of numbers to decide when is a good time to take a photograph, or maybe to choose the photograph that's really optimal in putting forward the best possible impression - and you might want to put forward different kinds of social impressions in different situations."
Unfortunately, just because people tend to judge people based on their faces in predictable ways, it doesn’t mean that their judgements are any good. Although some studies have found certain features that seem to predict personality traits (men with wider faces are more likely to cheat and lie for example) there are no grand formulas that definitively link appearance and personality.
So if you want people to think you're a more approachable person by all means give a big smile in that photo - but don't expect anyone grinning at you in Tinder to be a sweetheart when you meet them in real life.