Up to about age 3 years, children may have difficulty distinguishing between fantasy and reality. Thus, they will sometimes descote something as real that happened (or was modified) only in their imagination. By the age of your step-daughter, however, this is less likely.
Most of us lie for one of three or four basic reasons:
An attempt to avoid criticism or punishment—“I didn’t break the vase; don’t spank me.”
The desire to seem important or virtuous—“Look at the picture I drew; my teacher said it was the best one in our class.”
A wish to see someone else criticized or punished—“Janie smeared your lipstick on the wall.”
To get out of something we don’t want to do—“I don’t have any homework; it’s okay if I watch TV.”
Those reasons apply to 5-year-olds just as they do to you and me. With little children, however, (1) and (2) are the most likely explanations. Sometimes they get in the habit of “telling a story” because they are afraid—genuinely afraid— of what will happen to them if they tell the truth. Reflect back on a few recent episodes and see whether she has been punished too often or too severely for any and every minor infraction of family rules. And check to make certain that she gets some genuine praise for good things she does so she doesn’t have to make up a story that she expects to bring forth praise from you and your husband.
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.