With my son and grades I set up an email system with his teachers so I could ALREADY have test scores before he came home. HE KNEW this - it stopped a lot of lying which I think was a bad habit he got into. I would say "How did you do on the test?" and he would say "Did Ms. J email you?" and I would say "Yes, she did." and he would stomp off saying "Well then you already KNOW how I did." and that became the basis for a lot of "How did you do's?" He thought I knew EVERYTHING - and I got into the habit of knowing the answer before I asked him anything - it put HIM into the habit of telling me the truth - What he did then was just not tell me stuff he did that I didn't know about. So I don't have an answer - But I did find this article.
Unhappy Child
Insights for Parents:
Why Children Lie
Lying is a skill all children learn. It is a tool for avoiding blame or punishment, and for shoring up a poor self-image. While all children lie, some do it much more than others. Psychologists who study lying have found patterns that help predict which children will lie the most.
The key difference appears to be the emotional well-being of the child. Children who are chronic liars don't feel good about themselves. Even so, repeated lying can be a sign of several underlying problems, each of which requires a different response from parents.
The most common reasons for lying, particularly among younger children, is a fear of punishment. This is especially true when the punishment is severe or the parents have unrealistically high expectations for their children. For example, a colleague told me about a family she had been counseling. The five-year-old girl's stepfather insisted that she do such things as putting away all her clothes without being asked, and clearing the table after dinner. He punished her if she didn't. The girl would say she had done the chores, even if she'd (predictably) forgotten.
Although the stepfather complained about the girl's lying, the underlying issue was his inappropriate expectations of what a normal five-year-old could do. The child was handling the situation the best way she knew how. Given her limited abilities and powerlessness within the family, lying was actually an adaptive response.
Older school-age children will also lie to enhance their self-esteem and social status. For example, they may claim to have met a particular rock star, actor, or sports figure, or they may exaggerate their parents' wealth. Occasional lies like this are seldom anything to worry about, since they're to be expected in the course of children's games of one-upmanship.
But repeated lies about social status are a sign of trouble. They tell you that the child has a bad attitude about himself. Ask yourself why he might be feeling humiliated or worthless. Is he being ignored? Has he been the butt of jokes, or been belittled?
For older children, chronic lying is often a rebellion against restrictions. It is a way to challenge a parent's authority. Preteens no longer feel they must tell their parents everything they do; they may respond with a lie to what they perceive as an intrusive question.
As they grow older, children realize that the greatest control they can have is the control of information. Generally, the more intrusive or overinvolved parents are, the more likely it is that preadolescents will lie by omitting information. Often they do this blatantly, as if to emphasize their growing need for privacy. "Where did you go?" "Nowhere." What did you do?" "Nothing." "Who was there?" "Nobody you'd know."
A sudden increase in lying can also be a signal that something's wrong in the family. This is especially true if the child is acting out in other ways, such as stealing or committing vandalism. You should pay particular attention if the victims of the thefts or other petty crimes are other family members. Often this is a cry for help that is much louder than his words alone could be.
For example, it's not too unusual when counseling a preadolescent who has done something dramatic and new, such as stealing and crashing the family car, or who has been arrested for burglary, to discover that his parents were contemplating a divorce. Creating this crisis was the only way the child could think of to reunite his parents, if only for the moment. While his motivations were unconscious, his actions addressed his strong needs.
article copied from:
https://web.archive.org/web/20120416085052/http://www.drkutner.com/parenting/articles/lying.html