Young children may know they can deceive others but their first lies are often more humorous than effective. Imagine the child who claims not to have eaten any cake while her mouth is still full, or who blames the family dog for drawing on the wall. But is lying actually an important sign other cognitive skills are also developing? As a child matures how does the nature and motivation behind lying change? And is it ever a cause for concern? In this week's Woman's Hour Parenting Podcast, Jenni Murray speaks to consultant child and educational psychologist, Laverne Antrobus.