You need to hope that your four-year-old looks you in the eye and tells you a flat-out lie.  Actually that's not something you really have to hope for, because it will happen.  That's what four-year-olds do.  At a certain age, every child begins to realize that their world is not absolutely congruent with mommy and daddy's world.  It dawns on them that sometimes you're not in the same room.  Sometimes details escape mom and dad's attention. 

Mom didn't notice when I forgot to brush my teeth.  I dumped a handful of french fries behind daddy's car seat, and he didn't make me go back and pick them up.  I scratched the coffee table with the can opener and the world didn't come to an end. 

Suddenly they realize you may not be aware of everything they think, do and say.  Indeed, they become conscious of the concept that they may be able to "get away with stuff."  Don't panic, dad -- this is actually a good thing.  Realizing they are individuals separate from you is part of that process of discovering and trying out their independence.  Taking a long-term view, independence is the goal.  We want our kids to learn independent thinking so that they move out sometime before their thirtieth birthday.  However, knowing you have the ability to lie and choosing to lie are very different.

Be well prepared for that first lie.

That first lie told by a three-, four- or five-year-old is a landmark.  It's a moment of huge consequence during which a moral code begins to take shape. It's a fork in the road for any individual.  Please don't miss it.  Don't laugh off their little fib as just a cute inconsequential phase.  Don't be too tired to discipline your child that day.  Hope that you and your wife are not on a two-week cruise while your youngster discovers and perfects his new ability to deceive adults by practicing on his soft-hearted grammy or scattered-brained aunt.  Actually, you may not want to schedule too much time away from a child who may be heading toward that first prevarication.  It's that important.

Let's consider the scenario.  Your kid does something naughty.  Not malicious.  Just something that happens when a four-year-old is out of your sight for six minutes.  Sissy draws on the wall with her new Crayola markers. The twins put your cell phone in the microwave. Timmy shaves the cat.  You know they did it.  No doubt about it.  They even look guilty.

You ask what happened.  Timmy says, "I don‘t know."  You ask, "Did you shave the cat?"  Timmy says, "No."  You rephrase the question, "Did you cut the hair off Weeblefester's back?"  Then Timmy either gets panicky or defiant.  But he stills says, "No." 

This is all good news!  You've caught them in the act.  Dad, this is your chance to help them choose the right path from this day forward.

Make it a big deal

How do you respond?  This is not a time to yell or spank or send them to their room.  You are dealing with a crime of intellect. So use yours.  Make a speech.  A nice long speech.  Something like this:

"Oh, Timmy.  This makes me so sad.  Shaving the cat is a bad idea.  You shouldn't shave the cat.  But that's not what makes me sad.  What makes me sad is that you lied to me.  I asked, "Did you shave the cat?" and you said, "No."  You didn't tell daddy the truth.  You lied to me.  And you cannot do that.  Oh my goodness, lying is a bad, bad thing.  It's worse than shaving the cat.  It's worse than teasing your sister.  Timmy, look at me.  You cannot lie.  You must not lie.  If I ask you a question, you have to tell me the truth.  This is important.  You want to know how important?  A long time ago, God made a list of the ten rules.  He called them the Ten Commandments.  One of those rules was "Do not lie."  That's one of God's most important rules.  "Do not murder" and "Do not steal" are also on that list of rules.  You wouldn't kill someone, would you?  You wouldn't take something that wasn't yours, would you?  It's the same with "Do not lie."  It makes God sad.  It makes me sad.  Do you understand?  This is a big deal.  I need you to promise me that you will not lie to me ever again.  Do you know why?  Next time I ask you something, I need to know for sure that Timmy is telling the truth.  Timmy would not lie to me.  I can trust Timmy.  Son, I love you. You love me.  I know that for sure.  But I also need to know that when you tell me something, it is true!  Does this make sense?  Do you understand?  This is very important.  You know what?  I don't really care that you shaved the cat.  That was just a silly idea you had and I know you won't do it again.  I know you're sorry for shaving the cat.  But, please tell me that you will never lie to me or lie to mom ever again."