Want something from a stranger? Try smiling.

A new study has found that friendly, trustworthy faces are more likely to influence people who do not know you. Researcher Erik Schlicht and his team collected data from hundreds of one-shot rounds of Texas hold’em <a target="_blank" href="http://www.mademan.com/joe-cada-poker-champion-interview“>poker between 14 relative novices and hundreds of opponents. Each round the players received a two-card hand. Their opponents bet 5,000 chips. The players had to decide whether to fold (lose 100 chips guaranteed) or call (win or lose 5,000 chips). Before making a decision, the players saw a picture of their opponent’s face. The face was untrustworthy, neutral or trustworthy. The players had no idea how the opponent’s face correlated with playing style. 

Faces with neutral or untrustworthy expressions had no effect on the players. When players saw a trustworthy face, they took longer to decide and decreased their chances of winning by acting as if their opponent had a better hand. It was the perfect bluff. The researchers concluded that, contrary to the popular belief that the optimal face is neutral in appearance, poker players who bluff frequently could actually benefit from appearing trustworthy because the natural tendency is that a trustworthy-looking player bluffs less.

“What we found is that when the person appears to be trustworthy or friendly, the person reacting to the bet tends to fold more,” Schlicht told Made Man in a phone interview. “If your intention in the poker game is to bluff, then you would probably benefit from appearing trustworthy or friendly. This tends to work early in the game. People dynamically update their beliefs about you. Using this type of facial technique would only work early in the game with someone who does not really know what type of player you are.”

Schlicht is a cognitive scientist at Aptima and the study was conducted between his time at Harvard and Cal Tech. He is also an adjunct professor at Wellesley College. Schlicht said he enjoys playing poker, but the reason he chose the game was because it is an effective research tool for studying how people use opposing information and expected value to make decisions.

More than just poker

The smiling poker face technique only applies against people who have not had a chance to figure out how their opponents play. This, of course, has limited applications in game play. What makes the study noteworthy is its relevance outside of card games. The smiling poker face can be used in job interviews, while buying or selling, and with women, among other things.

“Anytime you’re dealing in negotiation, or an interrogation, or job interviews, anytime you’re involved in this exchange of interaction, this comes into play,” Schlicht said. “Those situations are not betting, but what they do offer is verbal information. They are saying, ‘I’m good for this job.’ Or in an interrogation setting, ‘I didn’t commit the crime.’ That’s their bet. How you interpret that information is going to depend on your read of them. If, as an interrogator, you see someone is smiling, or something to that effect, you might unconsciously believe them when maybe you shouldn’t.”

The decision to surrender to someone who is smiling can be conscious or subconscious. Some of the players in the study who folded against a smiling face said they did so by choice. Others said they paid no attention to the face, but still folded. The effect happens more often when the player has a mediocre hand. The player with the mediocre hand does not know what to do. He sees a smiling face and that is the final piece of information that leads him to fold. 

Over time the technique loses its power. Schlicht said that faces that portray unreliable information tend to be ignored. See: Congress.

(To learn more about this study click here and here and here.)