If you do this with your face you may be able to earn more money

A smile is a two-way street, according to new research.

While smiling often is associated with trustfulness and kindness (and can even harm your career), a smile can either increase or decrease perceptions of trustworthiness based on your personality.

Research published in the journal PLOS One examined prior research which suggests that people behave more cooperatively toward those who smile and less so toward those with personality pathology. In the study, researchers used the past research to “model the combined effects of smiles and personality pathology on trust.”

“I’ve had two lines of research in my career thus far. One investigates the communicative functions of facial expressions and the other investigates personality disorders. Here, I was able to combine these two lines by examining how people interact with others when given information about their emotional state (via their facial expression) and personality traits,” study author Lawrence Ian Reed, a clinical assistant professor at New York University, told PsyPost.

The study consisted of 262 participants who were asked to play an investment game – or “trust game – with another person. The catch was that the other person was just decoy created by researchers, where participants were given descriptors about the person which consisted of having a borderline personality disorder, antisocial personality disorder, or no personality pathology.

Participants were given an allowance of $0.50 and were free to decide how much of that sum they would give to the other person. The participants were told that they would receive triple the amount that they were to give the other person, while the researchers’ invention would either give back some of the amounts or keep it all.

The transfer of money indicated a level of trust, according to researchers, which they found that both smiles and certain personality traits helped influence.

Here’s a breakdown of the findings:

  • Participants dished less money when the other person had a borderline personality disorder or antisocial personality disorder.
  • Smiles increased the amount of money transferred for those with either borderline personality pathology or no personality pathology, but antisocial personality pathology amounted to decreased funds via transfer.

Reed told PsyPost that “both your emotional state and your personality traits affect the ways that people perceive you and interact with you. Depending upon your personality, a smile can increase or decrease how you are perceived and treated by others.”

“In most cases, a smile makes someone appear more trustworthy. However, when displayed by an individual with antisocial traits, a smile can make them appear less trustworthy. Think the Joker or some other conniving character,” he said.

A follow-up study with another 283 participants revealed similar results, but smiles increased the amount of money transferred to those with antisocial personality pathology.