Is lying - here I mean the concept of understanding that we can tell someone something that isn't true, and have them not know that it isn't - a learned understanding or a developmental thing? If toddlers never saw people say things that they knew not to be true, and saw people believe those things - would it occur to them to do it? Or does it come with the understanding that mummy etc doesn't know everything in terms of where the veggies went that she thought I ate but I'm actually sitting on? Just pondering.