Mine just started lying this year (he turned 6 and entered a new school and also got put in a group of kids who are more "street smart" than him). He was naive and innocent and guileless until recently. All I needed to do was ask and I was told chapter and verse of all his wrongdoings. But, I am a strict parent as far as behavior and social interaction are concerned and I hold DS up to very high standards and he will get punished and will hear about my disappointment in him. Though the punishment part is OK with him, the parental disappointment is too hard to bear for him because he is a sensitive little guy. So, he has started lying with a straight face when his behavior has been poor at school. I usually know what to expect and trap him by asking the same question in a different way at a different time. For e.g. So, how many people got time outs in class today? Answer: 3 (while in the previous version of the story, 2 of his friends got a time out and had to sit in the "thinking corner" for disrupting the class). Then I confront him and the truth usually comes out.
This takes a hawk eye, time, persistence and knowing how your child thinks. If the parent is very busy (like my spouse is) it is very hard to know these things and address them as these kids can be really smooth while lying. I am concerned that when he gets older and more savvy or if I am not too vigilant, I will be taken for a ride.
