Notice the person's eye movements. You can usually tell if a person is remembering something or making something up based on eye movements. When people remember details, their eyes move to the left if they are right-handed. When right-handed people make something up, their eyes move to the right. The reverse is true of left-handed people. People also tend to blink more rapidly ("eye flutter") as they're telling a lie. More common in men than in women, another tell of a lie can be rubbing the eyes.[1]
Watch the eyelids. These tend to close longer than the usual blink when a person sees or hears something he or she doesn't agree with.[2] However, this can be a very minute change, so you will need to know how the person blinks normally during a non-stressful situation for accurate comparison. If the hands or fingers also go to the eyes, this may be another indicator of trying to "block out" the truth.[2]4Do not use eye contact or lack of it as a sole indicator of truthfulness. Contrary to popular belief, a liar does not always avoid eye contact.[1] Humans naturally break eye contact and look at non-moving objects to help them focus and remember. Liars may deliberately make eye contact to seem more sincere; this can be practiced to overcome any discomfort, as a way of "proving" that truth is being told. Indeed, it has been shown that some liars tend to increase the level of eye contact in response to the fact that investigators have often considered eye contact as a tell.[2] Clearly, only use eye aversion as one indicator in a general context of increasing distress when being asked difficult questions.[2]
from -
http://www.wikihow.com/Detect-Lies not a great source but what i could do on the fly.
FWIW - If my memory is serving correct and I can't say it is, MR is a lefty.
