A machine learning tool trained to detect tell-tale signs of lying has been found to do better than the average person, using little more than data from wearable sensors that pick up teensy flickers in facial muscles. Developed by researchers at Tel Aviv University, Israel, the system correctly detected when people were lied 73 percent of the time, on average, and revealed two types of liars in the process. Wearable electrodes measured the movements of facial muscles in volunteers who either fibbed or told the truth, to feed a machine learning algorithm. The idea that genuine emotions can 'leak' onto the face of a liar is nothing new, though. Measuring, capturing, or even recognizing them is another matter: These involuntary, uncontrollable micro-expressions only appear for a split-moment, vanishing after 40 to 60 milliseconds. Much of the research to locate precise facial muscles that contort to form expressions has been done using a technique called facial surface electromyography, or sEMG.
It measures the electrical activity of facial muscles and is capable of registering expressions that are too subtle for humans to detect. This new study tested a new type of wearable electrodes designed to be more sensitive and comfortable than sEMG devices, and a machine learning tool trained to read facial expressions in video footage. Two people sat facing one another, rigged up to the electrodes. One person wore headphones and either repeated the word they heard or said something different, to mislead their partner who was trying to catch them out. The researchers recorded the activity of facial muscles between the eyebrows (called corrugator supercilia) and on the cheeks (zygomaticus major) of participants as they were listening to the audio cues, speaking, and responding. The study did find that among the 48 participants, people displayed different 'give-away' indicators. Some people activated their cheek muscles when lying, while others twitched muscles near their eyebrows.
More information:
https://www.sciencealert.com/new-lie-detector-can-read-facial-muscles-you-re-probably-not-aware-of