The dangerous thing about lying is people don't understand how the act changes us,"says Dan Ariely,behavioural psychologist at Duke University.Psychologists have documented children lying as early as the age of two.Some experts even consider lying a developmental milestone,like crawling and walking,because it requires sophisticated planning, attention and the ability to see a situation from someone else's perspective to manipulate them. But,for most people,lying gets limited as we develop a sense of morality and the ability to self-regulate.