When people tell lies, there are four underlying mechanisms at work:
- Arousal: Lying causes anxiety and arousal, either because of dissonance at conflicting values and behavior, or due to fear of getting caught. This can be detected via lie detectors, speech errors and hesitations, repetitions, fidgeting and displacement activity, blinking, higher vocal pitch and pupil dilation.
- Behavior control: We try to control body language that might give us away. In fact this is impossible and leakage often occurs, for example where we are controlling our face and our legs give us away.
- Emotion: Our emotions change when we are lying. For example, duping delight, where the liar is secretly pleased at their perceived success. Guilt may also appear. Micro-motions in facial muscles can betray hidden emotions.
- Thinking: To lie, we usually have to think a lot harder, such as to ensure coherence in our arguments. This leads us to take longer in speaking with more pauses. We also tend to use more generalities to avoid getting trapped by specific detail.
(Source: kenqyu)
