Joanna Fortune: My three-year-old son has started lying to me 

All children will tell a lie at some point. I would go so far as to say that lying is as much a developmental stage as learning to tell the truth. 

Children start to lie around the age of three when they realise their parents are not mind readers and don’t know everything, so they test the limits by experimenting with the truth. Examples include: “I’ve brushed my teeth”, “I didn’t take a biscuit”, etc.

Lying will typically increase between the ages of four and six, and by eight, many will have refined lying to the extent they can sometimes get away with it. Up to then, they tend to get caught or even own up to themselves.

When your child lies to you about the small stuff, here are some tips:

• Emphasise the importance of telling the truth in your family. Be far more interested in the truth and almost uninterested in the lie.
• Praise them for owning up and telling you the truth. Say something like, “I like it when you’re honest”, and focus on that without a consequence for the lie — the critical part is that they own up.
• Read books or stories with a life lesson about lying (The Boy Who Cried Wolf is the classic one) and ask your child what they thought about the story afterwards. Later, when they lie you can refer back to this story and ask if they remember what happened to the boy who cried wolf.

When it is a lie about the bigger and more important stuff, you need to address it directly. In the case of your three-year-old, it seems he is lying to avoid getting into trouble. 

It also sounds as though he needs support around managing his frustration in a way that won’t get him into trouble.

At his age, cause-and-effect thinking is underdeveloped and he is not hitting his sister to hurt her but to release his frustration.

Set a gentle yet firm boundary with both children: “We do not hit people, ever. I can help you with big feelings, so try calling me next time.”

Comfort the child who was hurt and support them in returning to play more calmly before you step back.

• For more on the topic of lying, listen to my podcast exa.mn/15-minute-lying
• If you have a question for Dr Joanna Fortune, please send it to parenting@examiner.ie