Brains of subjects unwittingly putting on a "smile" face responded to neutral faces as if they were smiling too. http://scan.oxfordjournals.org/content/10/10/1316.abstract?etoc …
@DegenRolf This is kind of a replication of a famous study by @FritzStrack of which a replication is going on now:http://www.psychologicalscience.org/index.php/publications/observer/obsonline/aps-registered-replication-report-project-to-explore-the-facial-feedback-hypothesis.html …