This might be somewhat of an unfortunate list, as I tend to do 1, 2, 3, and 5 when I'm answering a nuanced question that requires a careful answer (i.e. non-technical family member asking if it's really possible for the NSA to spy on all of us)
Yeah, I totally get it. I'm not saying they are absolute tells. But let's say you talk with somebody about an easy subject, during which they behave one way, and then you turn the discussion to a more sensitive topic that you suspect they may lie about. If they change their behavior from the established benchmark, then that can be one indicator in your diagnosis.
Couldn't it also just indicate that you've switched from an easy to a difficult subject? All you're really reading is emotion, which may or may not indicate deception.
Sure. But if you're asking someone where they were at the time of a crime -- e.g. Were you at Nicole Brown Simpson's house yesterday at 7pm? -- and that turns out to be a really difficult question for a person to answer, then maybe that's a signal that something more is going on.
