A two year old can understand when it has done something wrong if you explain it to them and use specific visual examples of why what they did was wrong. Two year old's have not full developed reasoning skills yet, they are still learning right from wrong. But they will understand if you keep explaining. A ten year old has fully developed their reasoning and understanding skills, they are still learning but they will deal with conflict much differently than a two year old. They should understand right from wrong and should have the skills to negotiate, listen and understand.
