Coders analyzed more than 23,000 frames of video from real-life cases in the US, Canada, Australia, and the UK. They compared the facial actions of 26 genuine pleaders to those of 26 liars.
By looking closely, researchers found some facial muscles "leak" signs of our true feelings during these intensely emotional and pressurized pleas to the public.
Genuine pleaders showed more contraction of two facial muscles related to grief and sadness: corrugator supercilii, one of the three muscles of the eyelid that helps wrinkle the forehead, and depressor anguli oris, a mouth muscle that is associated with frowning. In liars, they detected subtle contractions of the zygomatic major, a facial muscle linked with masking a smile, and full contraction of the frontalis muscle suggestive of a failed attempt to seem sad.ᔥ The Awl