Students at the MIT media lab have created a computer software which uses a specially designed algorithm to determine if a person's smile is genuine. It can tell if the person is smiling because they are happy or if they are smiling to hide their anger or frustration.
This is interesting because it could be used by law enforcement to help get truthful answers out of those they are interogating. With this technology we can see the truth about a person's intentions. As this technology advances we will be able to tell if someone if faking beind sad or if they are lying just based on their expression.
Below is an example of the same person with two different smiles, can you guess which is real.

http://www.popsci.com/files/imagecache/article_image_large/articles/smile.png
The one on the left is genuine while the one on the right is hiding frustration.
Boyle, R. (2012, May 29). Algorithm can tell if your smile is happy or born of frustration. Retrieved from http://www.popsci.com/technology/article/2012-05/new-
algorithm-computer-can-tell-if-your-smile-happy-or-borne-frustration