This signal refers to a static feature as may be present in a face after muscle toning from repeated facial contractions. A baseline level of muscular tension will exist tightening up the area around the nose, and progressing vertically across the face along the marionette lines.
Lighter effect on younger faces:
This signal reveals a psychology that is constantly connected to deeper emotions, and exists in a low-key state of affect. A high level of baseline tension will indicate a psychology with a habit of judging situations continually by how they relate to their personal ethical or emotional opinion. Often this comes out in such emotions as contempt, disgust, repulsion as well as giddiness, jolliness and vulnerability.
For much more information about this, visit: http://cognitivetype.boards.net/thread/1838/authenticity-fe-fi-smiles-extended