Why do children lie?

For this thread, let's consider other conditions in which children may not tell the "truth." Here you may use your experiences, but try to locate (preferably scholarly) articles or findings to back up your views. Do there seem to be gender or age differences?

(Here is one citation and one link for articles. One focuses on very young children.The Nature and Effects of Young Children's Lies - Wilson, Smith, Ross (2003). Social Development.

The other attempts to discuss this more globally:http://www.ncbi.nlm.nih.gov/pubmed/21887961 See if you can locate other articles about children of different ages.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2864928/

https://static.squarespace.com/static/54763f79e4b0c4e55ffb000c/t/5477ccf2e4b07347e76a53c9/1417137394112/how-and-where-does-moral-judgment-work.pdf

Can i get help with this ?