"Your smile gives you away"

"Smile and the whole world smiles with you? Well, not necessarily. "

In a winning scenario, smiling can decrease your odds of success against the same opponent in subsequent matches, according to new research presented by the USC Institute for Creative Technologies and sponsored by the U.S. Army Research Laboratory.

People who smiled during victory increased the odds of their opponent acting aggressively to steal a pot of money rather than share it in future gameplay, according to a paper presented in May at the International Conference on Autonomous Agents and Multiagent Systems by USC ICT research assistant Rens Hoegen, USC ICT research programmer Giota Stratou and Jonathan Gratch, director of virtual humans research at USC ICT and a professor of computer science at the USC Viterbi School of Engineering.

Conversely, researchers found smiling during a loss tended to help the odds of success in the game going forward.

The study is in line with previous research published by senior author Gratch, whose main interest lies both in how people express these tells—an unconscious action that betrays deception—and using this data to create artificial intelligence to discern and even express these same emotional cues as a person.

"We think that emotion is the enemy of reason. But the truth is that emotion is our way of assigning value to things," said Gratch. "Without it, we'd be faced with limitless choices."

(Link to more) via Drudge