Hopefully, all children learn that lying is not a good thing as soon as they learn their ABCs. For myself, I learned that lesson the hard way. I remember telling my Dad that it was really my friend that shot all the arrows at my sister's doll. Needless to say, that did not work. At some point all kids try a lie, get caught, and suffer the consequences. I'd like to say that my incident with the doll was the only time I tried lying, but that would be a lie.
Lying takes several forms for kids. Sometimes it is the straight out, "I did not do that" when you know they did. Another more subtle form is telling the story truthfully and leaving out certain details that the child conveniently "forgets" because they are self incriminating. After 30 years of working in schools, almost eight years as an administrator, and 22 years as a parent, I have heard almost everything. I once had seven students that were involved in a misadventure of some sort on the playground. When I spoke to each of them seperately, they all told the same story, except their own part in the rule breaking was entirely edited out.