Deception gains a slight edge over deception detection when the interactions are few in number and are among strangers. If you spend enough time with the people you interact with, they may leak their true intent through their behaviour. However, when interactions are anonymous or infrequent, behavioural cues cannot be read against a background of known behaviour, so more general attributes must be used. Because of the negative consequences of being detected, people are expected to be nervous when lying. In response to concern over appearing nervous, people may exert control, trying to suppress behaviour, with possible side effects detectable by the listener such as a planned, rehearsed impression. Lying is also cognitively demanding. You must suppress the truth and construct a falsehood that is plausible, then tell it in a convincing way and remember the story. Cognitive load appears to play the biggest role. When lies are not well-rehearsed, people have to think too hard, and this causes several effects, including overcontrol that leads to blinking and fidgeting less and using fewer hand gestures, longer pauses and higher-pitched voices. Of course, if self-deception is involved, you are less likely to give off the normal cues of lying that others might perceive.