Arguments about limits are a challenge to parents. A child will nag for permission and parents will explain once again "why not." The discussions may also serve as entertainment for a child looking for loopholes.

Kaitlyn: "But Mom, why can't I get my lip pierced?

Mom: "I already told you why, Kaitlyn.

 Kaitlyn: "I know, but can't I, pleeease? Mom: "No."

The next day it starts all over again: "Mom, Ashley had her eyebrow pierced, can I do it too?"

What events maintain Kaitlyn's nagging? The topic always brings disagreement, but she continues to bring it up. Mom and Dad try new reasons from time to time, but this only encourages Kaitlyn to try new answers in hope that eventually Mom and Dad will agree. Kaitlyn's parents need to pinpoint their reasons for their veto and then stick to them.

Mom: "Your father and I have decided you can't get any body piercings. It risks too much infection, it looks silly, and you're too young. Right, David?"

Dad: "Right."

Now will Kaitlyn stop nagging? Probably not, but if the reasons are quietly and monotonously repeated, the arguments will get shorter because the situation is now clear and fair. At least Kaitlyn's parents think so.

When you learn to drive a car, you don't need repeated lessons about pistons, transmissions and wires. As long as the accelerator, brake and steering wheel work consistently, you can learn very well. Learning becomes a nightmare if the car (or the instructor) is inconsistent, balking when cranky, difficult to start, or generally unreliable.

Children learn their habits in the same way. Understanding how the car engine works or why parents are anxious about certain situations may help, but repeated explanations will not.

In the early years of psychology, E. R. Guthrie and G. P. Horton studied this need for understanding. A cat was placed in a problem box. As most cat owners know, it is not in a cat's nature to be content in a confined place. A pole in the center of the box could open the door if the cat pushed it. As the cat paced around, it mewed and scratched and then it rubbed the pole the way a cat rubs a person's leg. The latch let go, a spring pulled the door aside, and the cat was free. When the cat was repeatedly placed in the same situation, it escaped faster and faster each time by rubbing the pole, releasing the latch (and snapping a picture of itself each time). The pictures showed that the cat didn't learn anything about latches and springs. Mechanical engineering is above a cat. It only learned the necessary: stand here, swing your rear against the pole, leave.

Children do the same. From rattles and noisy toys, to doorknobs and computers, to pleasing Daddy and Mommy, their skills develop and race far ahead of their understanding. So it's best to be brief and conservative with explanations of rules - especially when a son or daughter seems to be enjoying the argument.