Developmentally, when do children start to comprehend the meaning of telling a lie?

Fantasy and reality are easily mixed in a four year old's mind. When we were raising our children, we learned to define three categories of 'untruths.' 1. Fantasy. This is NOT to be punished but simply gently corrected so the child recognizes the difference between fantasy and reality. There are two ways of doing this that don't cause the child to be defensive: 1. Join in. "Mom, I saw this BIG monster down the street" "Yeah! I saw him too and he was green and I gave him a marshmallow!" "Oh, MOmmmmmmmm!" 2. Gently redirect by getting at the core of what is being said. "Mom, I saw this BIG monster down the street." "Oh, really? Was it bigger than the dog?" "It was bigger than the trees!" "Wow! It must have had a hard time walking! Did it fall down a lot?" While you are joining in here, you keep injecting bits of reality without challenging his fun with his imagination. 2. Defensive lies. "Did you take that cookie?" "NO!" -- that's a defensive lie. It an "I don't want to get in trouble" ...  more