New research by a Canadian team has bad news for liars. They filmed the responses of many adults to a variety of emotion-inducing scenes. Their finding: people who tried to hide their true feelings gave themselves away through “microexpressions” lasting as little as one twenty-fifth of a second.

These subjects were trying to mask such things as fear and disgust, but their microexpressions couldn’t lie to the camera. Researcher Stephen Porter said of this, “Unlike body language, you can’t monitor or completely control what’s going on in your face.” Since none of us carries around microexpression-catching cameras, of what practical use is this research?

Potentially, quite a lot.

Porter and his team are now studying videotapes of 60 known murder case liars with the hope that they will be able to develop a methodology for law enforcement officials to use this visual form of lie detection.