How To Tell If Someone Is Lying To You – Psychologist Reveals Top Three Tell-Tale Signs. If you have been looking for the surefire ways to tell if someone is lying to you or not, then these are the tips you need to consider. Some people can be masters of deceit, but this is how you can spot a big fat fibber. A man who has been dubbed the “human lie detector” reveals exactly how to rumble a liar. You may think you’re adept at spotting a faker, but apparently a lot of the usual tells are actually myths. New research reveals that 89% of Brits believe they know the top giveaways, with a lack of eye contact claiming the top spot (64%), followed by delayed responses (50%) and a change of tone (40%). Men and women also suspected behaviours such as fidgeting, sweating, scratching your nose and covering your mouth when speaking as surefire signs that someone is lying. However deception detection expert Darren Stanton said these clues are not as clear cut as they may seem. He ...