"It starts very young. Indeed, bright kids -- those who do better on other academic indicators.are able to start lying at 2 or 3. 'Lying is related to intelligence,' explains Dr. Victoria Talwar, an assistant professor at Montreal's McGill University and a leading expert on children's lying behavior.
"Although we think of truthfulness as a young child's paramount virtue, it turns out that lying is the more advanced skill. A child who is going to lie must recognize the truth, intellectually conceive of an alternate reality, and be able to convincingly sell that new reality to someone else. Therefore, lying demands both advanced cognitive development and social skills that honesty simply doesn't require. 'It's a developmental milestone,' Talwar has concluded.
"This puts parents in the position of being either damned or blessed, depending on how they choose to look at it. If your 4-year-old is a good liar, it's a strong sign she's got brains. And it's the smart, savvy kid who's most at risk of becoming a habitual liar."
-- from "Learning to Lie", by Po Bronson, New York magazine, 2008-02-10